Nuclear factor kappaB nuclear translocation upregulates c-Myc and p53 expression during NMDA receptor-mediated apoptosis in rat striatum

NMDA receptor-mediated Ca2+ signaling: Impact on cell cycle regulation and the development of neurodegenerative diseases and cancer

NMDA receptors are Ca2+-permeable ligand-gated ion channels that mediate fast excitatory transmission in the central nervous system. NMDA receptors regulate the proliferation and differentiation of neural progenitor cells and also play critical roles in neural plasticity, memory, and learning. In addition to their physiological role, NMDA receptors are also involved in glutamate-mediated excitotoxicity, which results from excessive glutamate stimulation, leading to Ca2+ overload, and ultimately to neuronal death. Thus, NMDA receptor-mediated excitotoxicity has been linked to several neurodegenerative diseases such as Alzheimer's, Parkinson's, Huntington's, dementia, and stroke. Interestingly, in addition to its effects on cell death, aberrant expression or activation of NMDA receptors is also involved in pathological cellular proliferation, and is implicated in the invasion and proliferation of various types of cancer. These disorders are thought to be related to the contribution of NMDA receptors to cell proliferation and cell death through cell cycle modulation. This review aims to discuss the evidence implicating NMDA receptor activity in cell cycle regulation and the link between aberrant NMDA receptor activity and the development of neurodegenerative diseases and cancer due to cell cycle dysregulation. The information presented here will provide insights into the signaling pathways and the contribution of NMDA receptors to these diseases, and suggests that NMDA receptors are promising targets for the prevention and treatment of these diseases, which are leading causes of death and disability worldwide.

The Multiple Roles of Autophagy in Neural Function and Diseases

Autophagy involves the sequestration and delivery of cytoplasmic materials to lysosomes, where proteins, lipids, and organelles are degraded and recycled. According to the way the cytoplasmic components are engulfed, autophagy can be divided into macroautophagy, microautophagy, and chaperone-mediated autophagy. Recently, many studies have found that autophagy plays an important role in neurological diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, neuronal excitotoxicity, and cerebral ischemia. Autophagy maintains cell homeostasis in the nervous system via degradation of misfolded proteins, elimination of damaged organelles, and regulation of apoptosis and inflammation. AMPK-mTOR, Beclin 1, TP53, endoplasmic reticulum stress, and other signal pathways are involved in the regulation of autophagy and can be used as potential therapeutic targets for neurological diseases. Here, we discuss the role, functions, and signal pathways of autophagy in neurological diseases, which will shed light on the pathogenic mechanisms of neurological diseases and suggest novel targets for therapies.

Myc beyond Cancer: Regulation of Mammalian Tissue Regeneration

Myc is one of the most well-known oncogenes driving tumorigenesis in a wide variety of tissues. From the brain to blood, its deregulation derails physiological pathways that grant the correct functioning of the cell. Its action is carried out at the gene expression level, where Myc governs basically every aspect of transcription. Indeed, in addition to its role as a canonical, chromatin-bound transcription factor, Myc rules RNA polymerase II (RNAPII) transcriptional pause-release, elongation and termination and mRNA capping. For this reason, it is evident that minimal perturbations of Myc function mirror malignant cell behavior and, consistently, a large body of literature mainly focuses on Myc malfunctioning. In healthy cells, Myc controls molecular mechanisms involved in pivotal functions, such as cell cycle (and proliferation thereof), apoptosis, metabolism and cell size, angiogenesis, differentiation and stem cell self-renewal. In this latter regard, Myc has been found to also regulate tissue regeneration, a hot topic in the research fields of aging and regenerative medicine. Indeed, Myc appears to have a role in wound healing, in peripheral nerves and in liver, pancreas and even heart recovery. Herein, we discuss the state of the art of Myc's role in tissue regeneration, giving an overview of its potent action beyond cancer.

PARP-1: a critical regulator in radioprotection and radiotherapy-mechanisms, challenges, and therapeutic opportunities

Background: Since its discovery, poly (ADP-ribose) polymerase 1 (PARP-1) has been extensively studied due to its regulatory role in numerous biologically crucial pathways. PARP inhibitors have opened new therapeutic avenues for cancer patients and have gained approval as standalone treatments for certain types of cancer. With continued advancements in the research of PARP inhibitors, we can fully realize their potential as therapeutic targets for various diseases. Purpose: To assess the current understanding of PARP-1 mechanisms in radioprotection and radiotherapy based on the literature. Methods: We searched the PubMed database and summarized information on PARP inhibitors, the interaction of PARP-1 with DNA, and the relationships between PARP-1 and p53/ROS, NF-κB/DNA-PK, and caspase3/AIF, respectively. Results: The enzyme PARP-1 plays a crucial role in repairing DNA damage and modifying proteins. Cells exposed to radiation can experience DNA damage, such as single-, intra-, or inter-strand damage. This damage, associated with replication fork stagnation, triggers DNA repair mechanisms, including those involving PARP-1. The activity of PARP-1 increases 500-fold on DNA binding. Studies on PARP-1-knockdown mice have shown that the protein regulates the response to radiation. A lack of PARP-1 also increases the organism's sensitivity to radiation injury. PARP-1 has been found positively or negatively regulate the expression of specific genes through its modulation of key transcription factors and other molecules, including NF-κB, p53, Caspase 3, reactive oxygen species (ROS), and apoptosis-inducing factor (AIF). Conclusion: This review provides a comprehensive analysis of the physiological and pathological roles of PARP-1 and examines the impact of PARP-1 inhibitors under conditions of ionizing radiation exposure. The review also emphasizes the challenges and opportunities for developing PARP-1 inhibitors to improve the clinical outcomes of ionizing radiation damage.

Everolimus attenuates glutamate-induced PC12 cells death

BACKGROUND

Glutamate-induced neuronal cell death plays a key role in neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Some recent studies reported the potential immunomodulatory and neuroprotective properties of inhibitors of serine-threonine kinase, mTOR (mammalian target of rapamycin). However, no study was conducted about the neuroprotective potential of everolimus (EVR), a selective and potent mTOR inhibitor. Therefore, this study was planned to investigate whether EVR has protective effects against glutamate-induced toxicity in PC12 cells, which are used as model for neurons injury, and to elucidate the underlying mechanism.

METHODS

PC12 cells were concurrently treated with glutamate (8 mM) and EVR (0-40 nM) for 24 h. Then, the cells viability, apoptosis rate, and apoptosis-related proteins (caspase-3, bax and bcl-2) were measured using MTT, annexin V/PI and immunoblotting assays.

RESULTS

Analyzing the protective effect of different concentrations of EVR (0-40 nM) against glutamate-induced cytotoxicity revealed a significant increase in cell viability in co-treatment regimen (p < 0.01). Also, EVR (40 nM) significantly (p < 0.01) inhibited glutamate-induced apoptosis through depressing the elevation of bax/bcl-2 ratio and expression of cleaved caspase-3, concentration depend.

CONCLUSION

The results demonstrated, for the first time, that EVR could protect against glutamate-mediated PC12 cell death via inhibiting apoptosis.

Obscure Involvement of MYC in Neurodegenerative Diseases and Neuronal Repair

MYC is well known as a potent oncogene involved in regulating cell cycle and metabolism. Augmented MYC expression leads to cell cycle dysregulation, intense cell proliferation, and carcinogenesis. Surprisingly, its increased expression in neurons does not induce their proliferation, but leads to neuronal cell death and consequent development of a neurodegenerative phenotype. Interestingly, while cancer and neurodegenerative diseases such as Alzheimer's disease are placed at the opposite sides of cell division spectrum, both start with cell cycle dysregulation and stimulation of proliferation. It seems that MYC action directed toward neuron cell proliferation and neural tissue repair collides with evolutional loss of regenerative capacity of CNS neurons in order to strengthen synaptic structure, to protect our cognitive abilities and therefore character. Accordingly, there are abundant mechanisms that block its expression and action specifically in the brain. Moreover, while MYC expression in brain neurons during neurodegenerative processes is related to their death, there are obvious evidences that MYC action after physical injury is beneficial in case of peripheral nerve recovery. MYC might be a useful tool to repair brain cells upon development of neurodegenerative disease or CNS trauma, including stroke and traumatic brain and spinal cord injury, as even imperfect axonal growth and regeneration strategies will likely be of profound benefit. Understanding complex control of MYC action in the brain might have important therapeutic significance, but also it may contribute to the comprehension of development of neurodegenerative diseases.

Glycine is a competitive antagonist of the TNF receptor mediating the expression of inflammatory cytokines in 3T3-L1 adipocytes

OBJECTIVE

To determine the involvement of TNF-α and glycine receptors in the inhibition of pro-inflammatory adipokines in 3T3-L1 cells.

METHODS

RT-PCR evidenced glycine receptors in 3T3-L1 adipocytes. 3T3-L1 cells were transfected with siRNA for the glycine (Glrb) and TNF1a (Tnfrsf1a) receptors and confirmed by confocal microscopy. Transfected cells were treated with glycine (10 mM). The expressions of TNF-α and IL-6 mRNA were measured by qRT-PCR, while concentrations were quantified by ELISA.

RESULTS

Glycine decreased the expression and concentration of TNF-α and IL-6; this effect did not occur in the absence of TNF-α receptor due to siRNA. In contrast, glycine produced only slight changes in the expression of TNF-α and IL-6 in the absence of the glycine receptor due to siRNA. A docking analysis confirmed the possibility of binding glycine to the TNF-α1a receptor.

CONCLUSION

These findings support the idea that glycine could partially inhibit the binding of TNF-α to its receptor and provide clues about the mechanisms by which glycine inhibits the secretion of pro-inflammatory adipokines in adipocytes through the TNF-α receptor.

Glaucoma and neuroinflammation: An overview

Glaucoma is an optic neuropathy characterized by well-defined optic disc morphological changes (i.e., cup enlargement, neuroretinal border thinning, and notching, papillary vessel modifications) consequent to retinal ganglion cell loss, axonal degeneration, and lamina cribrosa remodeling. These modifications tend to be progressive and are the main cause of functional damage in glaucoma. Despite the latest findings about the pathophysiology of the disease, the exact trigger mechanisms and the mechanism of degeneration of retinal ganglion cells and their axons have not been completely elucidated. Neuroinflammation may play a role in both the development and the progression of the disease as a result of its effects on retinal environment and retinal ganglion cells. We summarize the latest findings about neuroinflammation in glaucoma and examine the connection between risk factors, neuroinflammation, and retinal ganglion cell degeneration.

eNOS-dependent S-nitrosylation of the NF-κB subunit p65 has neuroprotective effects

Cell death by glutamate excitotoxicity, mediated by N-methyl-D-aspartate (NMDA) receptors, negatively impacts brain function, including but not limited to hippocampal neurons. The NF-κB transcription factor (composed mainly of p65/p50 subunits) contributes to neuronal death in excitotoxicity, while its inhibition should improve cell survival. Using the biotin switch method, subcellular fractionation, immunofluorescence, and luciferase reporter assays, we found that NMDA-stimulated NF-κB activity selectively in hippocampal neurons, while endothelial nitric oxide synthase (eNOS), an enzyme expressed in neurons, is involved in the S-nitrosylation of p65 and consequent NF-κB inhibition in cerebrocortical, i.e., resistant neurons. The S-nitro proteomes of cortical and hippocampal neurons revealed that different biological processes are regulated by S-nitrosylation in susceptible and resistant neurons, bringing to light that protein S-nitrosylation is a ubiquitous post-translational modification, able to influence a variety of biological processes including the homeostatic inhibition of the NF-κB transcriptional activity in cortical neurons exposed to NMDA receptor overstimulation.

NADPH protects against kainic acid-induced excitotoxicity via autophagy-lysosome pathway in rat striatum and primary cortical neurons

PURPOSE

To investigate the effects and mechanisms of NADPH on Kainic acid (KA)-induced excitotoxicity.

METHODS

KA, a non-N-methyl-d-aspartate glutamate receptor agonist, was exposed to adult SD rats via intrastriatal injection and rat primary cortical neurons to establish excitotoxic models in vivo and in vitro, respectively. To determine the effects of NADPH on KA-induced excitotoxicity, neuronal survival, neurologically behavioral score and oxidative stress were evaluated. To explore the mechanisms of neuroprotective effects of NADPH, the autophagy-lysosome pathway related proteins were detected.

RESULTS

In vivo, NADPH (1 mg/kg or 2 mg/kg) diminished KA (2.5 nmol)-induced enlargement of lesion size in striatum, improved KA-induced dyskinesia and reversed KA-induced activation of glial cells. Nevertheless, the neuroprotective effect of NADPH was not significant under the condition of autophagy activation. NADPH (2 mg/kg) inhibited KA (2.5 nmol)-induced down-regulation of TP-53 induced glycolysis and apoptosis regulator (TIGAR) and p62, and up-regulation of the protein levels of LC3-II/LC3-I, Beclin-1 and Atg5. In vitro, the excitotoxic neuronal injury was induced after KA (50 μM, 100 μM or 200 μM) treatment as demonstrated by decreased cell viability. Moreover, KA (100 μM) increased the intracellular levels of calcium and reactive oxygen species (ROS) and declined the levels of the reduced form of glutathione (GSH). Pretreatment of NADPH (10 μM) effectively reversed these changes. Meanwhile NADPH (10 μM) inhibited KA (100 μM)-induced down-regulation of TIGAR and p62, and up-regulation of the ratio of LC3-II/LC3-I, Beclin-1, Atg5, active-cathepsin B and active-cathepsin D.

CONCLUSIONS

Our data provide a possible mechanism that NADPH ameliorates KA-induced excitotoxicity by blocking the autophagy-lysosome pathway and up-regulating TIGAR along with its antioxidant properties.

Quantitative Subcellular Proteomics of the Orbitofrontal Cortex of Schizophrenia Patients

Schizophrenia is a chronic disease characterized by the impairment of mental functions with a marked social dysfunction. A quantitative proteomic approach using iTRAQ labeling and SRM, applied to the characterization of mitochondria (MIT), crude nuclear fraction (NUC), and cytoplasm (CYT), can allow the observation of dynamic changes in cell compartments providing valuable insights concerning schizophrenia physiopathology. Mass spectrometry analyses of the orbitofrontal cortex from 12 schizophrenia patients and 8 healthy controls identified 655 protein groups in the MIT fraction, 1500 in NUC, and 1591 in CYT. We found 166 groups of proteins dysregulated among all enriched cellular fractions. Through the quantitative proteomic analysis, we detect as the main biological pathways those related to calcium and glutamate imbalance, cell signaling disruption of CREB activation, axon guidance, and proteins involved in the activation of NF-kB signaling along with the increase of complement protein C3. Based on our data analysis, we suggest the activation of NF-kB as a possible pathway that links the deregulation of glutamate, calcium, apoptosis, and the activation of the immune system in schizophrenia patients. All MS data are available in the ProteomeXchange Repository under the identifier PXD015356 and PXD014350.

Nuclear factor-kappa β as a therapeutic target for Alzheimer's disease

Alzheimer's disease (AD) is a typical progressive, chronic neurodegenerative disorder with worldwide prevalence. Its clinical manifestation involves the presence of extracellular plaques and intracellular neurofibrillary tangles (NFTs). NFTs occur in brain tissues as a result of both Aβ agglomeration and Tau phosphorylation. Although there is no known cure for AD, research into possible cures and treatment options continues using cell-cultures and model animals/organisms. The nuclear factor-kappa β (NF-κβ) plays an active role in the progression of AD. Impairment to this signaling module triggers undesirable phenotypic changes such as neuroinflammation, activation of microglia, oxidative stress related complications, and apoptotic cell death. These imbalances further lead to homeostatic abnormalities in the brain or in initial stages of AD essentially pushing normal neurons toward the degeneration process. Interestingly, the role of NF-κβ signaling associated receptor-interacting protein kinase is currently observed in apoptotic and necrotic cell death, and has been reported in brains. Conversely, the NF-κβ signaling pathway has also been reported to be involved in normal brain functioning. This pathway plays a crucial role in maintaining synaptic plasticity and balancing between learning and memory. Since any impairment in the pathways associated with NF-κβ signaling causes altered neuronal dynamics, neurotherapeutics using compounds including, antioxidants, bioflavonoids, and non-steroidal anti-inflammatory drugs against such abnormalities offer possibilities to rectify aberrant excitatory neuronal activity in AD. In this review, we have provided an extensive overview of the crucial role of NF-κβ signaling in normal brain homeostasis. We have also thoroughly outlined several established pathomechanisms associated with NF-κβ pathways in AD, along with their respective therapeutic approaches.

Hydrogen sulfide: Therapeutic or injurious in ischemic stroke?

Hydrogen sulfide (H2S) has been identified as a vasodilatory, neuromodulatory, and anti-inflammatory gasotransmitter with antioxidant properties. Studies focused in cardiac tissue suggest H2S functions as a protective agent; however in the central nervous system (CNS) the effects of H2S during states of stress or injury, such as stroke, remain controversial. Currently, the application of H2S donors and modulators in stroke depends on the type of H2S donor and the timing of the therapy.

Inhibition of Karyopherin beta 1 suppresses prostate cancer growth

Prostate cancer (PCa) initiation and progression requires activation of numerous oncogenic signaling pathways. Nuclear-cytoplasmic transport of oncogenic factors is mediated by Karyopherin proteins during cell transformation. However, the role of nuclear transporter proteins in PCa progression has not been well defined. Here, we report that the KPNB1, a key member of Karyopherin beta subunits, is highly expressed in advanced prostate cancers. Further study showed that targeting KPNB1 suppressed the proliferation of prostate cancer cells. The knockdown of KPNB1 reduced nuclear translocation of c-Myc, the expression of downstream cell cycle modulators, and phosphorylation of regulator of chromatin condensation 1 (RCC1), a key protein for spindle assembly during mitosis. Meanwhile, CHIP assay demonstrated the binding of c-Myc to KPNB1 promoter region, which indicated a positive feedback regulation of KPNB1 expression mediated by the c-Myc. In addition, NF-κB subunit p50 translocation to nuclei was blocked by KPNB1 inhibition, which led to an increase in apoptosis and a decrease in tumor sphere formation of PCa cells. Furthermore, subcutaneous xenograft tumor models with a stable knockdown of KPNB1 in C42B PCa cells validated that the inhibition of KPNB1 could suppress the growth of prostate tumor in vivo. Moreover, the intravenously administration of importazole, a specific inhibitor for KPNB1, effectively reduced PCa tumor size and weight in mice inoculated with PC3 PCa cells. In summary, our data established the functional link between KPNB1 and PCa prone c-Myc, NF-kB, and cell cycle modulators. More importantly, inhibition of KPNB1 could be a new therapeutic target for PCa treatment.

Quinolinic Acid-Induced Huntington Disease-Like Symptoms Mitigated by Potent Free Radical Scavenger Edaravone-a Pilot Study on Neurobehavioral, Biochemical, and Histological Approach in Male Wistar Rats

In this study, we demonstrated for the first time the neuroprotective role of edaravone (Eda) (5 and 10 mg/kg b.w.), a potent free radical scavenger against the unilateral stereotaxic induction of quinolinic acid (QA) (300 nm/4 μl saline)-induced Huntington disease (HD)-like symptoms in behavioral, biochemical, and histological features in male Wistar rats striatum. QA induction, which mimics the early stage of HD, commonly causes oxidative stress to the cell and decreases the antioxidant defense mechanism by altering the level of lipid peroxidation (LPO), protein carbonyls, and nitrate concentration (NO) and the activities of glutathione family enzymes (GPx, GST, GR) and acetyl choline esterase concentration (AChE) which was found to be ameliorated by Eda treatment in both the tested doses 5 and 10 mg/kg b.w. in the significance of P < 0.05 and P < 0.01, respectively. Finally histopathological analysis by hematoxylin and eosin stain concluded the promising neurodefensive role of Eda in rat striatum at the dosage of 10 mg/kg b.w., with the decreased tissue damage and the number of damaged granular cells when compared to QA-induced groups.

NF-κB/p53-activated inflammatory response involves in diquat-induced mitochondrial dysfunction and apoptosis

Inflammation generated by environmental toxicants including pesticides could be one of the factors underlying neuronal cell damage in neurodegenerative diseases. In this study, we investigated the mechanisms by which inflammatory responses contribute to apoptosis in PC12 cells treated with diquat. We found that diquat induced apoptosis, as demonstrated by the activation of caspases and nuclear condensation, inhibition of mitochondrial complex I activity, and decreased ATP level in PC12 cells. Diquat also reduced the dopamine level, indicating that cell death induced by diquat is due to cytotoxicity of dopaminergic neuronal components in these cells. Exposure of PC12 cells to diquat led to the production of reactive oxygen species (ROS), and the antioxidant N-acetyl-cystein attenuated the cytotoxicity of caspase-3 pathways. These results demonstrate that diquat-induced apoptosis is involved in mitochondrial dysfunction through production of ROS. Furthermore, diquat increased expression of cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α) via inflammatory stimulation. Diquat induced nuclear accumulation of NF-κB and p53 proteins. Importantly, an inhibitor of NF-κB nuclear translocation blocked the increase of p53. Both NF-κB and p53 inhibitors also blocked the diquat-induced inflammatory response. Pretreatment of cells with meloxicam, a COX-2 inhibitor, also blocked apoptosis and mitochondrial dysfunction. These results represent a unique molecular characterization of diquat-induced cytotoxicity in PC12 cells. Our results demonstrate that diquat induces cell damage in part through inflammatory responses via NF-κB-mediated p53 signaling. This suggests the potential to generate mitochondrial damage via inflammatory responses and inflammatory stimulation-related neurodegenerative disease.

Microglia activation contributes to quinolinic acid-induced neuronal excitotoxicity through TNF-α

It has been reported that activation of NF-κB is involved in excitotoxicity; however, it is not fully understood how NF-κB contributes to excitotoxicity. The aim of this study is to investigate if NF-κB contributes to quinolinic acid (QA)-mediated excitotoxicity through activation of microglia. In the cultured primary cortical neurons and microglia BV-2 cells, the effects of QA on cell survival, NF-κB expression and cytokines production were investigated. The effects of BV-2-conditioned medium (BCM) on primary cortical neurons were examined. The effects of pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, and minocycline (MC), an inhibitor of microglia activation, on QA-induced excitotoxicity were assessed. QA-induced NF-κB activation and TNF-α secretion, and the roles of TNF-α in excitotoxicity were studied. QA at the concentration below 1 mM had no apparent toxic effects on cultured primary neurons or BV-2 cells. However, addition of QA-primed BCM to primary neurons did aggravate QA-induced excitotoxicity. The exacerbation of QA-induced excitotoxicity by BCM was partially ameliorated by inhibiting NF-κB and microglia activation. QA induced activation of NF-κB and upregulation of TNF-α in BV-2 cells. Addition of recombinant TNF-α mimicked QA-induced excitotoxic effects on neurons, and neutralizing TNF-α with specific antibodies partially abolished exacerbation of QA-induced excitotoxicity by BCM. These studies suggested that QA activated microglia and upregulated TNF-α through NF-κB pathway in microglia. The microglia-mediated inflammatory pathway contributed, at least in part, to QA-induced excitotoxicity.

Krabbe's leukodystrophy: Approaches and models in vitro

This Review describes some in vitro approaches used to investigate the mechanisms involved in Krabbe's disease, with particular regard to the cellular systems employed to study processes of inflammation, apoptosis, and angiogenesis. The aim was to update the knowledge on the results obtained from in vitro models of this neurodegenerative disorder and provide stimuli for future research. For a long time, the nonavailability of established neural cells has limited the understanding of neuropathogenic mechanisms in Krabbe's leukodystrophy. More recently, the development of new Krabbe's disease cell models has allowed the identification of neurologically relevant pathogenic cascades, including the major role of elevated psychosine levels. Thus, direct and/or indirect roles of psychosine in the release of cytokines, reactive oxygen species, and nitric oxide and in the activation of kinases, caspases, and angiogenic factors results should be clearer. In parallel, it is now understood that the presence of globoid cells precedes oligodendrocyte apoptosis and demyelination. The information described here will help to continue the research on Krabbe's leukodystrophy and on potential new therapeutic approaches for this disease that even today, despite numerous attempts, is without cure. © 2016 Wiley Periodicals, Inc.

Vinpocetine reduces diclofenac-induced acute kidney injury through inhibition of oxidative stress, apoptosis, cytokine production, and NF-κB activation in mice

Acute kidney injury (AKI) represents a complex clinical condition associated with significant morbidity and mortality. Approximately, 19-33% AKI episodes in hospitalized patients are related to drug-induced nephrotoxicity. Although, considered safe, non-steroidal anti-inflammatory drugs such as diclofenac have received special attention in the past years due to the potential risk of renal damage. Vinpocetine is a nootropic drug known to have anti-inflammatory properties. In this study, we investigated the effect and mechanisms of vinpocetine in a model of diclofenac-induced AKI. We observed that diclofenac increased proteinuria and blood urea, creatinine, and oxidative stress levels 24h after its administration. In renal tissue, diclofenac also increased oxidative stress and induced morphological changes consistent with renal damage. Moreover, diclofenac induced kidney cells apoptosis, up-regulated proinflammatory cytokines, and induced the activation of NF-κB in renal tissue. On the other hand, vinpocetine reduced diclofenac-induced blood urea and creatinine. In the kidneys, vinpocetine inhibited diclofenac-induced oxidative stress, morphological changes, apoptosis, cytokine production, and NF-κB activation. To our knowledge, this is the first study demonstrating that diclofenac-induced AKI increases NF-κB activation, and that vinpocetine reduces the nephrotoxic effects of diclofenac. Therefore, vinpocetine is a promising molecule for the treatment of diclofenac-induced AKI.

Anti-inflammatory and anti-excitoxic effects of diethyl oxopropanamide, an ethyl pyruvate bioisoster, exert robust neuroprotective effects in the postischemic brain

Ethyl pyruvate (EP) is a simple aliphatic ester of pyruvic acid and has been shown to have robust neuroprotective effects via its anti-inflammatory, anti-oxidative, and anti-apoptotic functions. In an effort to develop novel EP derivatives with greater protective potencies than EP, we generated four EP isosteres, among them the neuroprotective potency of N,N-diethyl-2-oxopropanamide (DEOPA), in which the ethoxy group of EP was replaced with diethylamine, was far greater than that of EP. When DEOPA was administered intravenously (5 mg/kg) to rat middle cerebral artery occlusion (MCAO) model at 6 hrs post-surgery, it suppressed infarct formation, ameliorated neurological and sensory/motor deficits, and inhibited microglial activation and neutrophil infiltrations in the postischemic brain more effectively than EP. In particular, DEOPA markedly suppressed LPS-induced nitrite production and cytokine/chemokine inductions in microglia, neutrophils, and endothelial cells and these effects are attributable to inhibition of the activity of NF-κB by suppressing IκB-α degradation and p65 to DNA binding. In addition, DEOPA suppressed NMDA-induced neuronal cell death in primary cortical neuron cultures by NAD replenishment and suppression of NF-κB activity. Together, these results indicate DEOPA has multi-modal protective effects against ischemic brain damage targeting numerous cell types in the brain and also against other inflammation-related diseases.

Study on the Mechanism of mTOR-Mediated Autophagy during Electroacupuncture Pretreatment against Cerebral Ischemic Injury

This study is aimed at investigating the association between the electroacupuncture (EA) pretreatment-induced protective effect against early cerebral ischemic injury and autophagy. EA pretreatment can protect cerebral ischemic and reperfusion injuries, but whether the attenuation of early cerebral ischemic injury by EA pretreatment was associated with autophagy is not yet clear. This study used the middle cerebral artery occlusion model to monitor the process of ischemic injury. For rats in the EA pretreatment group, EA pretreatment was conducted at Baihui acupoint before ischemia for 30 min for 5 consecutive days. The results suggested that EA pretreatment significantly increased the expression of autophagy in the cerebral cortical area on the ischemic side of rats. But the EA pretreatment-induced protective effects on the brain could be reversed by the specific inhibitor 3-methyladenine of autophagy. Additionally, the Pearson correlation analysis indicated that the impact of EA pretreatment on p-mTOR (2481) was negatively correlated with its impact on autophagy. In conclusion, the mechanism of EA pretreatment at Baihui acupoint against cerebral ischemic injury is mainly associated with the upregulation of autophagy expression, and its regulation of autophagy may depend on mTOR-mediated signaling pathways.

Neuronal Survival and p73/p63/p53: A Family Affair

Elucidating the mechanisms that regulate the life versus death of mammalian neurons is important not only for our understanding of the normal biology of the nervous system but also for our efforts to devise approaches to maintain neuronal survival in the face of traumatic injury or neurodegenerative disorders. Here, we review the emerging evidence that a key survival/death checkpoint in both peripheral and central neurons involves the p53 tumor suppressor and its newly discovered family members, p73 and p63. The full-length isoforms of these proteins function as proapoptotic proteins, whereas naturally occurring N-terminal truncated variants of p73 and p63 act as prosurvival proteins, at least partially by antagonizing the full-length family members. The authors propose that together, these isoforms comprise an upstream rheostat that sums different environmental cues to ultimately determine neuronal survival during development, during neuronal maintenance in adult animals, and even following traumatic injury.

Transcriptional regulation of microRNA-100, -146a, and -150 genes by p53 and NFκB p65/RelA in mouse striatal STHdh(Q7)/ Hdh(Q7) cells and human cervical carcinoma HeLa cells

MicroRNA (miRNA) genes generally share many features common to those of protein coding genes. Various transcription factors (TFs) and co-regulators are also known to regulate miRNA genes. Here we identify novel p53 and NFκB p65/RelA responsive miRNAs and demonstrate that these 2 TFs bind to the regulatory sequences of miR-100, -146a and -150 in both mouse striatal and human cervical carcinoma cells and regulate their expression. p53 represses the miRNAs while NFκB p65/RelA induces them. Further, we provide evidence that exogenous p53 inhibits NFκB p65/RelA activity by reducing its nuclear content and competing with it for CBP binding. This suggests for the existence of a functional cross-talk between the 2 TFs in regulating miRNA expression. Moreover, promoter occupancy assay reveals that exogenous p53 excludes NFκB p65/RelA from its binding site in the upstream sequence of miR-100 gene thereby causing its repression. Thus, our work identifies novel p53 and NFκB p65/RelA responsive miRNAs in human and mouse and uncovers possible mechanisms of co-regulation of miR-100. It is to be mentioned here that cross-talks between p53 and NFκB p65/RelA have been observed to define the outcome of several biological processes and that the pro-apoptotic effect of p53 and the pro-survival functions of NFκB can be largely mediated via the biological roles of the miRNAs these TFs regulate. Our observation with cell lines thus provides an important platform upon which further work is to be done to establish the biological significance of such co-regulation of miRNAs by p53 and NFκB p65/RelA.

Neuroprotective Effect of Resveratrol on Acute Brain Ischemia Reperfusion Injury by Measuring Annexin V, p53, Bcl-2 Levels in Rats

Background

Cerebral ischemia is as a result of insufficient cerebral blood flow for cerebral metabolic functions. Resveratrol is a natural phytoalexin that can be extracted from grape's skin and had potent role in treating the cerebral ischemia. Apoptosis, a genetically programmed cellular event which occurs after ischemia and leads to biochemical and morphological changes in cells. There are some useful markers for apoptosis like Bcl-2, bax, and p53. The last reports, researchers verify the apoptosis with early markers like Annexin V.

Methods

We preferred in this experimental study a model of global cerebral infarction which was induced by bilateral common carotid artery occlusion method. Rats were randomly divided into 4 groups : sham, ischemia-reperfusion (I/R), I/R plus 20 mg/kg resveratrol and I/R plus 40 mg/kg resveratrol. Statistical analysis was performed using Sigmastat 3.5 ve IBM SPSS Statistics 20. We considered a result significant when p<0.001.

Results

After administration of resveratrol, Bcl-2 and Annexin levels were significantly increased (p<0.001). Depending on the dose of resveratrol, Bcl2 levels increased, p53 levels decreased but Annexin V did not effected. P53 levels were significantly increased in ishemia group, so apoptosis is higher compared to other groups.

Conclusion

In the acute period, Annexin V levels misleading us because the apoptotic cell counts could not reach a certain level. Therefore we should support our results with bcl-2 and p53.

BAC transgenic mice provide evidence that p53 expression is highly regulated in vivo

p53 is an important tumor suppressor and stress response mediator. Proper control of p53 level and activity is tightly associated with its function. Posttranslational modifications and the interactions with Mdm2 and Mdm4 are major mechanisms controlling p53 activity and stability. As p53 protein is short-lived and hardly detectable in unstressed situations, less is known on its basal level expression and the corresponding controlling mechanisms in vivo. In addition, it also remains obscure how p53 expression might contribute to its functional regulation. In this study, we established bacterial artificial chromosome transgenic E.coli β-galactosidase Z gene reporter mice to monitor p53 expression in mouse tissues and identify important regulatory elements critical for the expression in vivo. We revealed preferentially high level of p53 reporter expressions in the proliferating, but not the differentiated compartments of the majority of tissues during development and tissue homeostasis. In addition, tumors as well as regenerating tissues in the p53 reporter mice also expressed high level of β-gal. Furthermore, both the enhancer box sequence (CANNTG) in the p53 promoter and the 3′ terminal untranslated region element were critical in mediating the high-level expression of the reporter. We also provided evidence that cellular myelocytomatosis oncogene was a critical player regulating p53 mRNA expression in proliferating cells and tissues. Finally, we found robust p53 activation preferentially in the proliferating compartment of mouse tissues upon DNA damage and the proliferating cells exhibited an enhanced p53 response as compared with cells in a quiescent state. Together, these results suggested a highly regulated expression pattern of p53 in the proliferating compartment controlled by both transcriptional and posttranscriptional mechanisms, and such regulated p53 expression may impose functional significance upon stress by setting up a precautionary mode in defense of cellular transformation and tumorigenesis.

Calcium-dependent intracellular signal pathways in primary cultured adipocytes and ANK3 gene variation in patients with bipolar disorder and healthy controls

Bipolar disorder (BD) is a chronic psychiatric disorder of public health importance affecting >1% of the Swedish population. Despite progress, patients still suffer from chronic mood switches with potential severe consequences. Thus, early detection, diagnosis and initiation of correct treatment are critical. Cultured adipocytes from 35 patients with BD and 38 healthy controls were analysed using signal pathway reporter assays, that is, protein kinase C (PKC), protein kinase A (PKA), mitogen-activated protein kinases (extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK)), Myc, Wnt and p53. The levels of activated target transcriptional factors were measured in adipocytes before and after stimulation with lithium and escitalopram. Variations were analysed in the loci of 25 different single-nucleotide polymorphisms (SNPs). Activation of intracellular signals in several pathways analysed were significantly higher in patients than in healthy controls upon drug stimulation, especially with escitalopram stimulation of PKC, JNK and Myc, as well as lithium-stimulated PKC, whereas no meaningful difference was observed before stimulation. Univariate analyses of contingency tables for 80 categorical SNP results versus diagnoses showed a significant link with the ANK3 gene (rs10761482; likelihood ratio χ(2)=4.63; P=0.031). In a multivariate ordinal logistic fit for diagnosis, a backward stepwise procedure selected ANK3 as the remaining significant predictor. Comparison of the escitalopram-stimulated PKC activity and the ANK3 genotype showed them to add their share of the diagnostic variance, with no interaction (15% of variance explained, P<0.002). The study is cross-sectional with no longitudinal follow-up. Cohorts are relatively small with no medication-free patients, and there are no 'ill patient' controls. It takes 3 to 4 weeks of culture to expand adipocytes that may change epigenetic profiles but remove the possibility of medication effects. Abnormalities in the reactivity of intracellular signal pathways to stimulation and the ANK3 genotype may be associated with pathogenesis of BD. Algorithms using biological patterns such as pathway reactivity together with structural genetic SNP data may provide opportunities for earlier detection and effective treatment of BD.

Chitosan oligosaccharides prevented retinal ischemia and reperfusion injury via reduced oxidative stress and inflammation in rats

The purpose of the present study was to investigate the protective effect and mechanism of chitosan oligonucleotides (COS) on retinal ischemia and reperfusion (I/R) injury. Rats pretreated with PBS, low-dose COS (5 mg/kg), or high-dose COS (10 mg/kg) were subjected to retinal ischemia by increasing their intraocular pressure to 130 mm Hg for 60 min. The protective effect of COS was evaluated by determining the electroretinograms (ERGs), morphology of the retina, and survival of retinal ganglion cells (RGCs). The oxidative damage was determined by imuunohistochemistry and ELISA, respectively. The expressions of inflammatory mediators (TNF-α, IL-1β, MCP-1, iNOS, ICAM-1) and apoptotic-related proteins (p53, Bax, Bcl-2) were quantified by PCR and Western blots. The detection of NF-κB p65 in the retina was performed by immunofluorescence. The protein levels of IκB and phosphorylated mitogen-activated protein kinases [MAPK; viz. extracellular signal-regulated protein kinases (ERK), c-Jun N-terminal kinases (JNK) and p38] and the NF-κB/DNA binding ability were assessed by Western blot analysis and EMSA. We found that pretreatment with COS, especially a high dosage, effectively ameliorated the I/R-induced reduction of the b-wave ratio in ERGs and the retinal thickness and the survival of RGCs at 24 h. COS decreased the expression of inflammatory mediators, p53 and Bax, increasing Bcl-2 expression and thereby reducing retinal oxidative damage and the number of apoptotic cells. More importantly, COS attenuated IκB degradation and p65 presence in the retina, thus decreasing NF-κB/DNA binding activity after I/R. In addition, COS decreased the phosphorylation levels of JNK and ERK but increased the phosphorylation level of p38. Pretreatment with p38 inhibitor (SB203580) abolished the protective effect of COS on retinal oxidative damage, as indicated by increased retinal 8-OHdG stains, and significantly increased the expression of inflammatory mediators (TNF-α, MCP-1, iNOS, ICAM-1) in I/R-injured rats. In conclusion, COS prevented retinal I/R injury through its inhibition of oxidative stress and inflammation. These effects were achieved by blocking the activation of NF-κB, JNK, and ERK but promoting the activation of p38 activation.

Apelin-13 attenuates traumatic brain injury-induced damage by suppressing autophagy

The adipocytokine apelin is a peptide, Apelin and its receptor are abundantly expressed in the nervous and cardiovascular systems. Previous studies had found apelin-13 reduces brain injuries and postischemic cerebral edema through blocking programmed cell death, Apelin-13 is also able to inhibit glucose deprivation induced cardiomyocyte autophagy in a concentration dependent fashion. To observe the effect of Apelin-13 on the brain injury induced by traumatic brain injury (TBI), and explore the effect of Apelin-13 on autophagy in TBI, We performed The neurological test, and the numbers of TBI-induced neural cell death were also counted by propidium iodide labeling. At last, the autophagy associated proteins LC3, Beclin-1, Bcl-2, p62 were also assessed with western-blotting. Compared with saline vehicle groups, the neural cell death, lesion volume, and neural dysfunction were attenuated by apelin-13 after TBI. In additionally, Apelin-13 also reversed TBI induced downregulation of LC3, Beclin-1, Bcl-2, p62 expression, compared with saline vehicle groups, at 24 and 48 h post TBI. Apelin-13 attenuates TBI induced brain damage by suppressing autophagy. All these results revealed that Apelin-13 suppressed autophagy. The autophagy may be involved in the mechanism of Apelin-13 rescue the subsequent damaged neuron in TBI.

Anti-inflammatory and antiapoptotic effects of mesenchymal stem cells transplantation in rat brain with cerebral ischemia

BACKGROUND

Excessive inflammation and apoptosis contribute to the pathogenesis of ischemic brain damage. Nuclear factor-kappa B (NF-κB) is considered to be a key protein complex involved in this cascade of events. The aim of the present study was to clarify the protection mechanism of the mesenchymal stem cells (MSCs).

METHODS

Lewis rats (N = 90) were randomly assigned to three groups: (1) the sham-operated group; (2) the saline group, in which the animals underwent rat transient middle cerebral artery occlusion (tMCAO, for 2 hours) and were treated with saline through the tail vein; and (3) the MSCs group, in which the animals underwent tMCAO (for 2 hours) and were infused with cultured human MSCs (4 × 10(6)/0.4 ml PBS) through the tail vein. At days 1 and 3 post-MSCs infusion, real-time PCR, and Western blot, immunohistochemical analyses were applied for tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and P-IKKβ, p53, and B-cell lymphoma 2 (Bcl-2) expression levels.

RESULTS

TNF-α, IL-1β messenger RNA (mRNA) and P-IκB-α, P-IKKβ, p53 protein expression levels were significantly increased in the saline group compared with the sham group. However, IκB-α and Bcl-2 protein expression levels were markedly decreased in the saline group. After injection of BrdU(+) MSCs, the expression levels of TNF-α, IL-1β mRNA and P-IκB-α, P-IKKβ, p53 protein were significantly decreased. Contrary to these findings, IκB-α, Bcl-2 protein expression levels were markedly increased. In addition, we found that infarct area was significantly reduced in MSCs group.

CONCLUSIONS

These results suggest that MSCs' neuroprotection is attributable to its anti-inflammatory and antiapoptotic effect through inhibition of NF-κB.

Liguzinediol improved the heart function and inhibited myocardial cell apoptosis in rats with heart failure

AIM

Liguzinediol is a novel derivative of ligustrazine isolated from the traditional Chinese medicine Chuanxiong (Ligusticum wallichii Franch), and produces significant positive inotropic effect in isolated rat hearts. In this study we investigated the effects of liguzinediol on a rat model of heart failure.

METHODS

To induce heart failure, male SD rats were injected with doxorubicin (DOX, 2 mg/kg, ip) once a week for 4 weeks. Then the rats were administered with liguzinediol (5, 10, 20 mg·kg(-1)·d(-1), po) for 2 weeks. Hemodynamic examination was conducted to evaluate heart function. Myocardial cell apoptosis was examined morphologically. The expression of related genes and proteins were analyzed using immunohistochemical staining and Western blot assays, respectively.

RESULTS

Oral administration of liguzinediol dose-dependently improved the heart function in DOX-treated rats. Electron microscopy revealed that liguzinediol (10 mg·kg(-1)·d(-1)) markedly attenuated DOX-induced injury of cardiomyocytes, and decreased the number of apoptotic bodies in cardiomyocytes. Furthermore, liguzinediol significantly decreased Bax protein level, and increased Bcl-2 protein level in cardiomyocytes of DOX-treated rats, led to an increase in the ratio of Bcl-2/Bax. Moreover, liguzinediol significantly decreased the expression of both cleaved caspase-3 and NF-κB in cardiomyocytes of DOX-treated rats. Administration of digitalis (0.0225 mg·kg(-1)·d(-1)) also markedly improved the heart function and the morphology of cardiomyocytes in DOX-treated rats.

CONCLUSION

Liguzinediol improves the heart function and inhibits myocardial cell apoptosis in the rat model of heart failure, which is associated with regulating Bcl-2, Bax, caspase-3 and NF-κB expression.

Ethyl pyruvate ameliorates 3-nitropropionic acid-induced striatal toxicity through anti-neuronal cell death and anti-inflammatory mechanisms

The potential neuroprotective value of ethyl pyruvate (EP) for the treatment of the striatal toxicity is largely unknown. We investigated whether EP promotes the survival of striatal neurons in a 3-nitropropionic acid (3-NP)-induced mouse model of Huntington's disease (HD). EP (5, 10, 20, and 40mg/kg/day, i.p.) was daily injected from 30min before 3-NP intoxication (pretreatment) and from onset/progression/peak point of neurological impairment by 3-NP intoxication. EP produced a neuroprotective effect in dose- and time-dependant manners. EP pretreatment of 40mg/kg/day produced the best neuroprotective effect among other conditions. Pretreatment of EP significantly attenuated neurological impairment and lethality and prevented formation of lesion area and neuronal loss in the striatum after 3-NP intoxication. This neuroprotection afforded by EP was associated with the suppression of succinate dehydrogenase activity, apoptosis, and microglial activation. The suppressive effect of EP corresponded to the down-regulation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signal pathways, and mRNA expression of inflammatory mediators including tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, inducible nitric oxide synthase, and cyclooxygenase-2 in the striatum after 3-NP intoxication. Interestingly, the intrathecal introduction of inhibitors MAPKs and NF-κB into control mice decreased the lethality after 3-NP intoxication. Our findings indicate that EP may effectively alleviate 3-NP-induced striatal toxicity by inhibition of the MAPKs and NF-κB pathways in the striatum, and that EP has a wide therapeutic window, suggesting that EP may have therapeutic value in the treatment of aspects of HD's disease related to inflammation.

Novel osmotin attenuates glutamate-induced synaptic dysfunction and neurodegeneration via the JNK/PI3K/Akt pathway in postnatal rat brain

The glutamate-induced excitotoxicity pathway has been reported in several neurodegenerative diseases. Molecules that inhibit the release of glutamate or cause the overactivation of glutamate receptors can minimize neuronal cell death in these diseases. Osmotin, a homolog of mammalian adiponectin, is a plant protein from Nicotiana tabacum that was examined for the first time in the present study to determine its protective effects against glutamate-induced synaptic dysfunction and neurodegeneration in the rat brain at postnatal day 7. The results indicated that glutamate treatment induced excitotoxicity by overactivating glutamate receptors, causing synaptic dysfunction and neuronal apoptosis after 4 h in the cortex and hippocampus of the postnatal brain. In contrast, post-treatment with osmotin significantly reversed glutamate receptor activation, synaptic deficit and neuronal apoptosis by stimulating the JNK/PI3K/Akt intracellular signaling pathway. Moreover, osmotin treatment abrogated glutamate-induced DNA damage and apoptotic cell death and restored the localization and distribution of p53, p-Akt and caspase-3 in the hippocampus of the postnatal brain. Finally, osmotin inhibited glutamate-induced PI3K-dependent ROS production in vitro and reversed the cell viability decrease, cytotoxicity and caspase-3/7 activation induced by glutamate. Taken together, these results suggest that osmotin might be a novel neuroprotective agent in excitotoxic diseases.

Functional RIG-I-like receptors control the survival of mesenchymal stem cells

Because of their potent regenerative and immunomodulatory properties, mesenchymal stem cells (MSCs) have promising therapeutic benefits in clinical treatment of inflammatory and infectious diseases. Recent studies suggest that many biological activities of MSCs are largely determined by pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs). However, the role of PRRs in regulating the survival of MSCs remains unknown. In the present study, we examined the viability of MSCs after stimulation of distinct PRRs. Activation of TLRs by direct addition with their respective ligands showed no significant effect on the survival of MSCs, whereas transfection with double-stranded RNA (dsRNA) resulted in marked cell death in MSCs. Transfection of dsRNA upregulated cytosolic retinoic acid inducible gene I (RIG-I)-like receptors (RLRs), including RIG-I and melanoma differentiation-associated antigen 5 (MDA5). Moreover, transfection of dsRNA activated downstream transcription factors interferon regulatory factor 3 (IRF3) and nuclear factor κB (NF-κB), as well as induced the expression of interferon-β (IFN-β) and pro-inflammatory cytokine interleukin 6 (IL-6) via RLR signaling. Furthermore, we found that transfection of dsRNA triggered both extrinsic and intrinsic apoptotic responses via RLRs. However, ectopic expression of RIG-I or MDA5 was not sufficient to induce apoptosis of MSCs without dsRNA transfection. Our study also revealed that IκB kinase α/β (IKKα/β) was required for RLR-mediated apoptosis in MSCs, while TANK-binding kinase 1 (TBK1)/IKKɛ served a pro-survival role. Moreover, neither overexpression of B-cell lymphoma 2 (Bcl2) nor neutralizing autocrined IFN-β reduced RLR-mediated apoptosis. In addition, autophagy was induced upon activation of RLRs, however, blocking autophagy did not rescue MSCs from the dsRNA-induced cell death. To the best of our knowledge, this is the first study to explore the role of RLRs in controlling the survival of MSCs, which may provide a clue to understand the pathogenesis of viral infection in MSCs.

Amantadine improves cognitive outcome and increases neuronal survival after fluid percussion traumatic brain injury in rats

This study evaluated the effects of clinically relevant concentrations of amantadine (AMT) on cognitive outcome and hippocampal cell survival in adult rats after lateral fluid percussion traumatic brain injury (TBI). AMT is an antagonist of the N-methyl-D-aspartate-type glutamate receptor, increases dopamine release, blocks dopamine reuptake, and has an inhibitory effect on microglial activation and neuroinflammation. Currently, AMT is clinically used as an antiparkinsonian drug. Amantadine or saline control was administered intraperitoneally, starting at 1 h after TBI followed by dosing three times daily for 16 consecutive days at 15, 45, and 135 mg/kg/day. Terminal blood draws were obtained from TBI rats at the time of euthanasia at varying time points after the last amantadine dose. Pharmacokinetics analysis confirmed that the doses of AMT achieved serum concentrations similar to those observed in humans receiving therapeutic doses (100-400 mg/day). Acquisition of spatial learning and memory retention was assessed using the Morris water maze (MWM) on days 12-16 after TBI. Brain tissues were collected and stained with Cresyl-violet for long-term cell survival analysis. Treatment with 135mg/kg/day of AMT improved acquisition of learning and terminal cognitive performance on MWM. The 135-mg/kg/day dosing of AMT increased the numbers of surviving CA2-CA3 pyramidal neurons at day 16 post-TBI. Overall, the data showed that clinically relevant dosing schedules of AMT affords neuroprotection and significantly improves cognitive outcome after experimental TBI, suggesting that it has the potential to be developed as a novel treatment of human TBI.

Cathepsin L plays a role in quinolinic acid-induced NF-Κb activation and excitotoxicity in rat striatal neurons

The present study seeks to investigate the role of cathepsin L in glutamate receptor-induced transcription factor nuclear factor-kappa B (NF-κB) activation and excitotoxicity in rats striatal neurons. Stereotaxic administration of the N-methyl-d-aspartate (NMDA) receptor agonist Quinolinic acid (QA) into the unilateral striatum was used to produce the in vivo excitotoxic model. Co-administration of QA and the cathepsin L inhibitor Z-FF-FMK or 1-Naphthalenesulfonyl-IW-CHO (NaphthaCHO) was used to assess the contribution of cathepsin L to QA-induced striatal neuron death. Western blot analysis and cathepsin L activity assay were used to assess the changes in the levels of cathepsin L after QA treatment. Western blot analysis was used to assess the changes in the protein levels of inhibitor of NF-κB alpha isoform (IκB-α) and phospho-IκB alpha (p-IκBα) after QA treatment. Immunohistochemical analysis was used to detect the effects of Z-FF-FMK or NaphthaCHO on QA-induced NF-κB. Western blot analysis was used to detect the effects of Z-FF-FMK or NaphthaCHO on QA-induced IκB-α phosphorylation and degradation, changes in the levels of IKKα, p-IKKα, TP53, caspase-3, beclin1, p62, and LC3II/LC3I. The results show that QA-induced loss of striatal neurons were strongly inhibited by Z-FF-FMK or NaphthaCHO. QA-induced degradation of IκB-α, NF-κB nuclear translocation, up-regulation of NF-κB responsive gene TP53, and activation of caspase-3 was strongly inhibited by Z-FF-FMK or NaphthaCHO. QA-induced increases in beclin 1, LC3II/LC3I, and down-regulation of p62 were reduced by Z-FF-FMK or NaphthaCHO. These results suggest that cathepsin L is involved in glutamate receptor-induced NF-κB activation. Cathepsin L inhibitors have neuroprotective effects by inhibiting glutamate receptor-induced IκB-α degradation and NF-κB activation.

Assessing competence of broccoli consumption on inflammatory and antioxidant pathways in restraint-induced models: estimation in rat hippocampus and prefrontal cortex

A growing body of evidence advocated the protective and therapeutic potential of natural compounds and phytochemicals used in diets against pathological conditions. Herein, the outcome of dietary whole broccoli consumption prior to restraint stress has been investigated in the hippocampus and prefrontal cortex of male rats, two important regions involved in the processing of responses to stressful events. Interestingly, a region-specific effect was detected regarding some of antioxidant defense system factors: nuclear factor erythroid-derived 2-related factor 2 (Nrf-2) antioxidant pathway, mitochondrial prosurvival proteins involved in mitochondrial biogenesis, and apoptotic cell death proteins. Dietary broccoli supplementation modulated the restraint-induced changes towards a consistent overall protection in the hippocampus. In the prefrontal cortex, however, despite activation of most of the protective factors, presumably as an attempt to save the system against the stress insult, some detrimental outcomes such as induced malate dehydrogenase (MDA) level and cleaved form of caspase-3 were detectable. Such diversity may be attributed in one hand to the different basic levels and/or availability of defensive mechanisms within the two studied cerebral regions, and on the other hand to the probable dose-dependent and hormetic effects of whole broccoli. More experiments are essential to demonstrate these assumptions.

"Super p53" mice display retinal astroglial changes

Tumour-suppressor genes, such as the p53 gene, produce proteins that inhibit cell division under adverse conditions, as in the case of DNA damage, radiation, hypoxia, or oxidative stress (OS). The p53 gene can arrest proliferation and trigger death by apoptosis subsequent to several factors. In astrocytes, p53 promotes cell-cycle arrest and is involved in oxidative stress-mediated astrocyte cell death. Increasingly, astrocytic p53 is proving fundamental in orchestrating neurodegenerative disease pathogenesis. In terms of ocular disease, p53 may play a role in hypoxia due to ischaemia and may be involved in the retinal response to oxidative stress (OS). We studied the influence of the p53 gene in the structural and quantitative characteristics of astrocytes in the retina. Adult mice of the C57BL/6 strain (12 months old) were distributed into two groups: 1) mice with two extra copies of p53 (“super p53”; n = 6) and 2) wild-type p53 age-matched control, as the control group (WT; n = 6). Retinas from each group were immunohistochemically processed to locate the glial fibrillary acidic protein (GFAP). GFAP+ astrocytes were manually counted and the mean area occupied for one astrocyte was quantified. Retinal-astrocyte distribution followed established patterns; however, morphological changes were seen through the retinas in relation to p53 availability. The mean GFAP+ area occupied by one astrocyte in “super p53” eyes was significantly higher (p<0.05; Student’s t-test) than in the WT. In addition, astroglial density was significantly higher in the “super p53” retinas than in the WT ones, both in the whole-retina (p<0,01 Student’s t-test) and in the intermediate and peripheral concentric areas of the retina (p<0.05 Student’s t-test). This fact might improve the resistance of the retinal cells against OS and its downstream signalling pathways.

DRAM1 regulates autophagy flux through lysosomes

We have previously reported that the mitochondria inhibitor 3-nitropropionic acid (3-NP), induces the expression of DNA damage-regulated autophagy modulator1 (DRAM1) and activation of autophagy in rat striatum. Although the role of DRAM1 in autophagy has been previously characterized, the detailed mechanism by which DRAM1 regulates autophagy activity has not been fully understood. The present study investigated the role of DRAM1 in regulating autophagy flux. In A549 cells expressing wilt-type TP53, 3-NP increased the protein levels of DRAM1 and LC3-II, whereas decreased the levels of SQSTM1 (sequestosome 1). The increase in LC3-II and decrease in SQSTM1 were blocked by the autophagy inhibitor 3-methyl-adenine. Lack of TP53 or knock-down of TP53 in cells impaired the induction of DRAM1. Knock-down of DRAM1 with siRNA significantly reduced 3-NP-induced upregulation of LC3-II and downregulation of SQSTM1, indicating DRAM1 contributes to autophagy activation. Knock-down of DRAM1 robustly decreased rate of disappearance of induced autophagosomes, increased RFP-LC3 fluorescence dots and decreased the decline of LC3-II after withdraw of rapamycin, indicating DRAM1 promotes autophagy flux. DRAM1 siRNA inhibited lysosomal V-ATPase and acidification of lysosomes. As a result, DRAM1 siRNA reduced activation of lysosomal cathepsin D. Similar to DRAM1 siRNA, lysosomal inhibitors E64d and chloroquine also inhibited clearance of autophagosomes and activation of lysosomal cathapsin D after 3-NP treatment. These data suggest that DRAM1 plays important roles in autophagy activation induced by mitochondria dysfunction. DRAM1 affects autophagy through argument of lysosomal acidification, fusion of lysosomes with autophagosomes and clearance of autophagosomes.

The protective effects of the proteasome inhibitor bortezomib (velcade) on ischemia-reperfusion injury in the rat retina

Purpose

To evaluate the protective effects of bortezomib (Velcade) on ischemia-reperfusion (IR) injury in the rat retina.

Methods

The rats were randomized to receive treatment with saline, low-dose bortezomib (0.05 mg/kg), or high-dose bortezomib (0.2 mg/kg) before the induction of IR injury. Electroretinography (ERG) was used to assess functional changes in the retina. The expression of inflammatory mediators (iNOS, ICAM-1, MCP-1, TNF-α), anti-oxidant proteins (heme oxygenase, thioredoxin, peroxiredoxin), and pro-apoptotic proteins (p53, bax) were quantified by PCR and western blot analysis. An immunofluorescence study was performed to detect the expression of iNOS, oxidative markers (nitrotyrosine, 8-OHdG, acrolein), NF-κB p65, and CD 68. Apoptosis of retinal cells was labeled with in situ TUNEL staining. Neu-N staining was performed in the flat-mounted retina to evaluate the density of retinal ganglion cells.

Results

ERG showed a decreased b-wave after IR injury, and pretreatment with bortezomib, especially the high dosage, reduced the functional impairment. Bortezomib successfully reduced the elevation of inflammatory mediators, anti-oxidant proteins, pro-apoptotic proteins and oxidative markers after IR insult in a dose-dependent manner. In a similar fashion, NF-κB p65- and CD 68-positive cells were decreased by bortezomib treatment. Retinal cell apoptosis in each layer was attenuated by bortezomib. The retinal ganglion cell density was markedly decreased in the saline and low-dose bortezomib groups but was not significantly changed in the high-dose bortezomib group.

Conclusions

Bortezomib had a neuro-protective effect in retinal IR injury, possibly by inhibiting the activation of NF-κB related to IR insult and reducing the inflammatory signals and oxidative stress in the retina.

The pro-survival role of autophagy depends on Bcl-2 under nutrition stress conditions

Autophagy can be induced under nutrition stress conditions. Bcl-2 is a pro-survival protein which inhibits apoptosis and autophagy. However, the role of Bcl-2 in autophagy regulation and cell survival under nutrition deprivation has not been fully understood. This study sought to investigate if Bcl-2 upregulation is essential in limiting autophagic activity and prevent cell death under nutrition deprivation conditions. Autophagic activity was monitored by the changes in GFP-LC3 localization and protein levels of Beclin1, LC3-II, cathepsin D and p62 in neuroblastoma SH-SY5Y cells underwent serum deprivation. Manipulation of Bcl-2 function was achieved with siRNAs and small molecular inhibitors. The cell viability and apoptosis were assessed with MTT assay and Annexin V/PI staining. The results showed that serum starvation increased protein levels of LC3-II and Beclin1 but decreased autophagy substrate p62. Autophagy activation induced by serum deprivation and rapamycin was accompanied by an upregulation of Bcl-2 protein levels. When Bcl-2 was knocked down with siRNA or inhibited with HA 14-1 or ABT-737, serum starvation induced profound cell death and enhanced autophagic flux under nutrition deprivation conditions, while knockdown of autophagic gene Beclin1 or autophagy inhibitors (bafilomycin A1 and E64D), rescued cell death. In contrast, overexpression of Bcl-2 inhibited autophagy and blocked cell death in response to serum deprivation. These data suggest that Bcl-2 plays an essential role in limiting autophagy activation and preventing initiation of programmed cell death. Thus Bcl-2 may be an important mechanism for balancing beneficial and detrimental impacts of autophagy on cell survival.

Propofol prevents cerebral ischemia-triggered autophagy activation and cell death in the rat hippocampus through the NF-κB/p53 signaling pathway

Propofol (2,6-diisopropylphenol) has been shown to attenuate neuronal injury under a number of experimental conditions; however, the mechanisms involved in its neuroprotective effects remain unclear. We therefore investigated whether inhibition of p53 induction by propofol contributes to the neuroprotection of cerebral ischemic cell death through both autophagic and apoptotic mechanisms. A transient global cerebral ischemia-reperfusion (I/R) model was produced with a 10-min, 2-vessel occlusion. The change in target genes including damage-regulated autophagy modulator (DRAM), microtubule-associated protein 1 light chain 3 (LC3), Beclin 1, cathepsin D, cathepsin B, p53-upregulated modulator of apoptosis (PUMA), Bax and Bcl-2 upon p53 inhibition was assessed with the co-administration of the intravenous anesthetic propofol and 3-methyladenine (3-MA), Pifithrin-alpha (PFT-α) or SN50. The I/R-induced increases of protein levels of p53 and LC3-II were significantly inhibited by treatment with propofol, 3-MA or PFT-α. The I/R-induced increases of protein levels of DRAM, Beclin 1, active cathepsin D and cathepsin B were significantly inhibited by treatment with propofol, PFT-α or SN50. The negative effects of the I/R-induced up-regulation of PUMA and Bax and the down-regulation of Bcl-2 in the rat hippocampus were all blocked by treatment with propofol, PFT-α or SN50. Our results suggest that cerebral I/R can induce nuclear factor-kappa B-dependent expression of p53. The autophagic and apoptotic mechanisms participate in programed cell death by regulating the p53-mediated pathway. Our results are the first to show that propofol, at clinically relevant concentrations, attenuated cell death through both autophagic and apoptotic mechanisms in the rat hippocampus after a cerebral I/R insult.

The endoplasmic reticulum stress inhibitor salubrinal inhibits the activation of autophagy and neuroprotection induced by brain ischemic preconditioning

AIM

To investigate whether endoplasmic reticulum (ER) stress participates in the neuroprotective effects of ischemic preconditioning (IPC)-induced neuroprotection and autophagy activation in rat brains.

METHODS

The right middle cerebral artery in SD rats was occluded for 10 min to induce focal cerebral IPC, and was occluded permanently 24 h later to induce permanent focal ischemia (PFI). ER stress inhibitor salubrinal (SAL) was injected via intracerebral ventricle infusion 10 min before the onset of IPC. Infarct volume and motor behavior deficits were examined after the ischemic insult. The protein levels of LC3, p62, HSP70, glucose-regulated protein 78 (GRP 78), p-eIF2α and caspase-12 in the ipsilateral cortex were analyzed using immunoblotting. LC3 expression pattern in the sections of ipsilateral cortex was observed with immunofluorescence.

RESULTS

Pretreatment with SAL (150 pmol) abolished the neuroprotective effects of IPC, as evidenced by the significant increases in mortality, infarct volume and motor deficits after PFI. At the molecular levels, pretreatment with SAL (150 pmol) significantly increased p-eIF2α level, and decreased GRP78 level after PFI, suggesting that SAL effectively inhibited ER stress in the cortex. Furthermore, the pretreatment with SAL blocked the IPC-induced upregulation of LC3-II and downregulation of p62 in the cortex, thus inhibiting the activation of autophagy. Moreover,SAL blocked the upregulation of HSP70, but significantly increased the cleaved caspase-12 level, thus promoting ER stress-dependent apoptotic signaling in the cortex.

CONCLUSION

ER stress-induced autophagy might contribute to the neuroprotective effect of brain ischemic preconditioning.

Activation of nuclear factor-κB in the brain after experimental subarachnoid hemorrhage and its potential role in delayed brain injury

It has been reported that inflammation is involved in brain injury after subarachnoid hemorrhage (SAH). Nuclear factor-κB (NF-κB) is a key transcriptional regulator of inflammatory genes. Here, we used pyrrolidine dithiocarbamate(PDTC), an inhibitor of NF-κB, through intracisternal injection to study the role of NF-κB in delayed brain injury after SAH. A total of 55 rabbits were randomly divided into five groups: the control group; the SAH groups including Day-3, 5, and 7 SAH groups (the rabbits in these groups were sacrificed at 3, 5, 7 days after SAH, respectively); and the PDTC group (n = 11 for each group). Electrophoretic mobility shift assay (EMSA) was performed to detect NF-κB DNA-binding activity. The mRNA levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and intercellular adhesion molecule (ICAM)-1 were evaluated by RT-PCR analysis. Deoxyribonucleic acid fragmentation was detected by TUNEL and p65 immunoactivity was assessed by immunohistochemistry. Our results showed the activation of NF-κB after SAH, especially at day 3 and 5. The activated p65 was detected in neurons. NF-κB DNA-binding activity was suppressed by intracisternal administration of PDTC. Increased levels of the TNF-α, IL-1β, and ICAM-1 mRNA were found in the brain at day 5 after SAH, and which were suppressed in the PDTC group. The number of TUNEL-positive cells also decreased significantly in the PDTC group compared with that in the Day-5 SAH group. These results demonstrated that the activated NF-κB in neurons after SAH plays an important role in regulating the expressions of inflammatory genes in the brain, and ultimately contributes to delayed brain injury.