Stimulus-dependent activation of NF-kappaB specifies apoptosis or neuroprotection in cerebellar granule cells

Hypericum perforatum: a comprehensive review on pharmacognosy, preclinical studies, putative molecular mechanism, and clinical studies in neurodegenerative diseases

The herb Hypericum perforatum, also referred to as St. John's wort, has drawn a lot of interest because of its potential therapeutic benefits in treating neurodegenerative illnesses. Due to the absence of effective therapies, illnesses like Alzheimer's and Parkinson's disease pose an increasing worldwide health concern. Because of its wide variety of phytochemicals, especially hyperforin, and hypericin, Hypericum perforatum is well known for its neuroprotective properties. These substances have proven to be able to affect different cellular processes linked to neurodegeneration. They can act as anti-inflammatory, antioxidant, and neurotransmitter system regulators, which may help halt neurodegenerative illnesses' progression. The use of Hypericum perforatum extracts and its contents has shown encouraging results in research on animal models of neurodegenerative disorders. These advantages include higher nerve cell survival, lowered oxidative stress, and higher cognitive performance. Underscoring its versatile potential to combat neurodegeneration, Hypericum perforatum has neuroprotective mechanisms that modulate neuroinflammation and prevent apoptotic pathways. In conclusion, Hypericum perforatum shows tremendous promise as a potential treatment for neurological illnesses due to its wide variety of phytochemicals. To completely comprehend its specific mechanisms of action and turn these discoveries into efficient clinical therapies, additional research is needed. Investigating Hypericum perforatum's function in neurodegenerative disorders may present new opportunities for the advancement of ground-breaking therapeutic strategies.

The role and therapeutic potential of nuclear factor κB (NF-κB) in ischemic stroke

Stroke is a prevalent cerebrovascular condition with a global impact, causing significant rates of illness and death. Despite extensive research, the available treatment options for stroke remain restricted. Hence, it is crucial to gain a deeper understanding of the molecular mechanisms associated with the onset and advancement of stroke in order to establish a theoretical foundation for novel preventive and therapeutic approaches. NF-κB, also known as nuclear factor κB, is a transcription factor responsible for controlling the expression of numerous genes and plays a crucial role in diverse physiological processes. NF-κB is triggered and regulates neuroinflammation and other processes after stroke, promoting the generation of cytokine storms and contributing to the advancement of ischemic stroke (IS). Therefore, NF-κB could potentially play a vital role in stroke by regulating diverse pathophysiological processes. This review provides an overview of the functions of NF-κB in stroke and its governing mechanisms. In addition, our attention is directed towards various potential therapies that aim to inhibit the NF-κB signaling pathway in order to offer valuable insights for the advancement of innovative treatment approaches for stroke.

Hypericin as a potential drug for treating Alzheimer's disease and type 2 diabetes with a view to drug repositioning

AIMS

Alzheimer's disease (AD) and type 2 diabetes (T2D) are two of the most common diseases in elderly population and they have a high rate of comorbidity. Study has revealed that T2D is a major risk factor of AD, and thus exploring therapeutic approaches that can target both diseases has drawn much interest in recent years. In this study, we tried to explore drugs that could be potentially used to prevent or treat both AD and T2D via a drug repositioning approach.

METHODS

We first searched the known drugs that may be effective to T2D treatment based on the network distance between the T2D-associated genes and drugs deposited in the DrugBank database. Then, via molecular docking, we further screened these drugs by examining their interaction with islet amyloid polypeptide (IAPP) and Aβ42 peptide, the key components involved in the pathogenesis of T2D or AD. Finally, the binding between the selected drug candidates and the target proteins was verified by molecular dynamics (MD) simulation; and the potential function of the drug candidates and the corresponding targets were analyzed.

RESULTS

From multiple resources, 734 T2D-associated genes were collected, and a list of 1109 drug candidates for T2D was obtained. We found that hypericin had the lowest binding energy and the most stable interaction with either IAPP or Aβ42 peptide. In addition, we also found that the target genes regulated by hypericin were differentially expressed in the tissues related to the two diseases.

CONCLUSION

Our results show that hypericin may be able to bind with IAPP and Aβ42 stably and prevent their accumulation, and thus could be a promising drug candidate for treating the comorbidity of AD and T2D.

Parathyroid Hormone Related Protein (PTHrP)-Associated Molecular Signatures in Tissue Differentiation and Non-Tumoral Diseases

Parathyroid-hormone-related protein (PTHrP) is encoded by the PTHLH gene which, via alternative promoter usage and splicing mechanisms, can give rise to at least three isoforms of 139, 141, and 173 amino acids with distinct C-terminals. PTHrP is subjected to different post-translational processing that generates smaller bioactive forms, comprising amino terminus, mid-region (containing a nuclear/nucleolar targeting signal), and carboxy terminus peptides. Both the full-length protein and the discrete peptides are key controllers of viability, proliferation, differentiation, and apoptosis in diverse normal and pathological biological systems via the reprogramming of gene expression and remodulation of PKA or PKC-mediated signalization mechanisms. The aim of this review is to pick up selected studies on PTHrP-associated signatures as revealed by molecular profiling assays, focusing on the available data about exemplary differentiating, differentiated, or nontumoral cell and tissue models. In particular, the data presented relate to adipose, bone, dental, cartilaginous, and skin tissues, as well as intestinal, renal, hepatic, pulmonary, and pancreatic epithelia, with a focus on hepatic fibrosis-, pancreatitis-, and diabetes-related changes as diseased states. When reported, the biochemical and/or physiological aspects associated with the specific molecular modulation of gene expression and signal transduction pathways in the target model systems under examination are also briefly described.

Role of NF-κB during Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis (M. tb) causes tuberculosis infection in humans worldwide, especially among immunocompromised populations and areas of the world with insufficient funding for tuberculosis treatment. Specifically, M. tb is predominantly exhibited as a latent infection, which poses a greater risk of reactivation for infected individuals. It has been previously shown that M. tb infection requires pro-inflammatory and anti-inflammatory mediators to manage its associated granuloma formation via tumor necrosis factor-α (TNF-α), interleukin-12 (IL-12), interferon-γ (IFN-γ), and caseum formation via IL-10, respectively. Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) has been found to play a unique mediator role in providing a pro-inflammatory response to chronic inflammatory disease processes by promoting the activation of macrophages and the release of various cytokines such as IL-1, IL-6, IL-12, and TNF-α. NF-κB's role is especially interesting in its mechanism of assisting the immune system's defense against M. tb, wherein NF-κB induces IL-2 receptors (IL-2R) to decrease the immune response, but has also been shown to crucially assist in keeping a granuloma and bacterial load contained. In order to understand NF-κB's role in reducing M. tb infection, within this literature review we will discuss the dynamic interaction between M. tb and NF-κB, with a focus on the intracellular signaling pathways and the possible side effects of NF-κB inactivation on M. tb infection. Through a thorough review of these interactions, this review aims to highlight the role of NF-κB in M. tb infection for the purpose of better understanding the complex immune response to M. tb infection and to uncover further potential therapeutic methods.

New metallophamaceutic reduced renal injury induced by non-steroidal anti-inflammatory

Purpose

To evaluate the effect of Rut-bpy (Cis-[Ru(bpy)2(SO3)(NO)]PF 6), a novel nitric oxide donor, able to modulate the histological changes caused by the NASID (meloxicam).

Methods

Wistar rats were assigned into three groups (n=6 rats/group): Sham group (saline solution), NSAID group (meloxicam - 15 mg/kg) and Rut-bpy group (100 mg/kg of Rut-bpy associated with 15mg/kg of meloxicam). At the end of experiments, kidneys were removed for histological study, fractal dimension and lacunarity in all animals.

Results

At the histological examination, all animals (six animals – 100 %) in the NSAID group had membrane thickening and other changes (necrosis, acute tubular congestion and vascular congestion); on the other hand, only one animal (16.6 %) of the Rut-bpy group had congestion. The fractal dimension and lacunarity were greater in the control and Rut-bpy group than in NSAIDs group (p<0.05).

Conclusion

Rut-bpy may prevent renal histological changes in rats caused by meloxicam.

Association between nucleotide-binding oligomerization domain protein 2 (NOD2) gene polymorphisms and Parkinson's disease (PD) susceptibility

Objective: This study aimed to explore the association between single nucleotide polymorphisms (SNPs) of nucleotide-binding oligomerization domain protein 2 (NOD2) gene and Parkinson's disease susceptibility, including IVS4 + 10A > C (rs72796353) and a missense mutation at exon 9 (c.2857A > G p.K953E). Methods: Rs72796353 and c.2857A > G p.K953E polymorphisms of NOD2 gene were genotyped via polymerase chain reaction-restriction fragment length polymorphism in 125 cases with PD and 120 healthy controls. Genotype and allele frequencies differences of gene polymorphisms between the case and control groups were analyzed by the Chi-square test. Odds ratio (OR) and 95% confidence interval (95%CI) were used to indicate the relative susceptibility to PD. Furthermore, Hardy-Weinberg equilibrium (HWE) was evaluated by the χ² test in controls. Results: Neither genotypes nor allele of rs72796353 was significantly different in cases and control groups (p > .05). Differently, AG/GG genotype of NOD2 2857 A > G polymorphism were associated with the increased risk of PD (OR = 2.486, 95%CI = 1.223-5.056), and G allele carriers were 2.563 times risk to suffer from PD (OR = 2.563, 95%CI = 1.310-5.013). Besides, AG genotype might be also a risk factor for PD. Conclusion: NOD2 c.2857A > G p.K953E polymorphism may be correlated with PD susceptibility in Chinese Han population, but not rs727796353. Further study should be conduct to certify this conclusion.

BARHL1 Is Downregulated in Alzheimer's Disease and May Regulate Cognitive Functions through ESR1 and Multiple Pathways

The Transcription factor BarH like homeobox 1 (BARHL1) is overexpressed in medulloblastoma and plays a role in neurogenesis. However, much about the BARHL1 regulatory networks and their functions in neurodegenerative and neoplastic disorders is not yet known. In this study, using a tissue microarray (TMA), we report for the first time that BARHL1 is downregulated in hormone-negative breast cancers and Alzheimer’s disease (AD). Furthermore, using an integrative bioinformatics approach and mining knockout mouse data, we show that: (i) BARHL1 and Estrogen Receptor 1 (ESR1) may constitute a network that regulates Neurotrophin 3 (NTF3)- and Brain Derived Neurotrophic Factor (BDNF)-mediated neurogenesis and neural survival; (ii) this is probably linked to AD pathways affecting aberrant post-translational modifications including SUMOylation and ubiquitination; (iii) the BARHL1-ESR1 network possibly regulates β-amyloid metabolism and memory; and (iv) hsa-mir-18a, having common key targets in the BARHL1-ESR1 network and AD pathway, may modulate neuron death, reduce β-amyloid processing and might also be involved in hearing and cognitive decline associated with AD. We have also hypothesized why estrogen replacement therapy improves AD condition. In addition, we have provided a feasible new mechanism to explain the abnormal function of mossy fibers and cerebellar granule cells related to memory and cognitive decline in AD apart from the Tau and amyloid pathogenesis through our BARHL1-ESR1 axis.

Valproic acid increases NF-κB transcriptional activation despite decreasing DNA binding ability in P19 cells, which may play a role in VPA-initiated teratogenesis

The nuclear factor-kappa B (NF-κB) family of transcription factors regulate gene expression in response to diverse stimuli. We previously demonstrated that valproic acid (VPA) exposure in utero decreases total cellular protein expression of the NF-κB subunit p65 in CD-1 mouse embryos with a neural tube defect but not in phenotypically normal littermates. This study evaluated p65 mRNA and protein expression in P19 cells and determined the impact on DNA binding ability and activity. Exposure to 5mM VPA decreased p65 mRNA and total cellular protein expression however, nuclear p65 protein expression was unchanged. VPA reduced NF-κB DNA binding and nuclear protein of the p65 DNA-binding partner, p50. NF-κB transcriptional activity was increased with VPA alone, despite decreased phosphorylation of p65 at Ser276, and when combined with tissue necrosis factor α. These results demonstrate that VPA increases NF-κB transcriptional activity despite decreasing DNA binding, which may play a role in VPA-initiated teratogenesis.

Regulation of Survival Motor Neuron Protein by the Nuclear Factor-Kappa B Pathway in Mouse Spinal Cord Motoneurons

Survival motor neuron (SMN) protein deficiency causes the genetic neuromuscular disorder spinal muscular atrophy (SMA), characterized by spinal cord motoneuron degeneration. Since SMN protein level is critical to disease onset and severity, analysis of the mechanisms involved in SMN stability is one of the central goals of SMA research. Here, we describe the role of several members of the NF-κB pathway in regulating SMN in motoneurons. NF-κB is one of the main regulators of motoneuron survival and pharmacological inhibition of NF-κB pathway activity also induces mouse survival motor neuron (Smn) protein decrease. Using a lentiviral-based shRNA approach to reduce the expression of several members of NF-κB pathway, we observed that IKK and RelA knockdown caused Smn reduction in mouse-cultured motoneurons whereas IKK or RelB knockdown did not. Moreover, isolated motoneurons obtained from the severe SMA mouse model showed reduced protein levels of several NF-κB members and RelA phosphorylation. We describe the alteration of NF-κB pathway in SMA cells. In the context of recent studies suggesting regulation of altered intracellular pathways as a future pharmacological treatment of SMA, we propose the NF-κB pathway as a candidate in this new therapeutic approach.

Astrocytes: Key Regulators of Neuroinflammation

Astrocytes are crucial regulators of innate and adaptive immune responses in the injured central nervous system. Depending on timing and context, astrocyte activity may exacerbate inflammatory reactions and tissue damage, or promote immunosuppression and tissue repair. Recent literature has unveiled key factors and intracellular signaling pathways that govern astrocyte behavior during neuroinflammation. Here we have re-visited in vivo studies on astrocyte signaling in neuroinflammatory models focusing on evidences obtained from the analysis of transgenic mice where distinct genes involved in ligand binding, transcriptional regulation and cell communication have been manipulated in astrocytes. The integration of in vivo observations with in vitro data clarifies precise signaling steps, highlights the crosstalk among pathways and identifies shared effector mechanisms in neuroinflammation.

Neuroprotective Activity of Hypericum perforatum and Its Major Components

Hypericum perforatum is a perennial plant, with worldwide distribution, commonly known as St. John's wort. It has been used for centuries in traditional medicine for the treatment of several disorders, such as minor burns, anxiety, and mild to moderate depression. In the past years, its antidepressant properties have been extensively studied. Despite that, other H. perforatum biological activities, as its neuroprotective properties have also been evaluated. The present review aims to provide a comprehensive summary of the main biologically active compounds of H. perforatum, as for its chemistry, pharmacological activities, drug interactions and adverse reactions and gather scattered information about its neuroprotective abilities. As for this, it has been demonstrated that H. perforatum extracts and several of its major molecular components have the ability to protect against toxic insults, either directly, through neuroprotective mechanisms, or indirectly, through is antioxidant properties. H. perforatum has therefore the potential to become an effective neuroprotective therapeutic agent, despite further studies that need to be carried out.

Neuroprotective Effects of (-)-Epigallocatechin-3-Gallate Against Focal Cerebral Ischemia/Reperfusion Injury in Rats Through Attenuation of Inflammation

Stroke is the second leading cause of death among adults worldwide. (-)-Epigallocatechin-3-gallate (EGCG) has been demonstrated to exhibit neuroprotective functions in cerebral ischemia/reperfusion injury. However, the underlying mechanisms in this process and its contribution to the protection function remain unknown. The current study examined the neuroprotective effects of EGCG after transient middle cerebral artery occlusion (tMCAO) in rats. tMCAO for 120 min was induced in male Sprague-Dawley rats treated with EGCG (50 mg/kg, i.p.) or Vehicle immediately after reperfusion. Neurological score, infarct ratio and inflammation-related molecules (assessed by 2,3,5-triphenyltetrazolium chloride, enzyme-linked immunosorbent assays, quantitative real-time PCR or western blotting) were estimated at 24 h after operation. EGCG prevented the impairment of neurological function and decreased the infarct volume, compared with the Vehicle group. The inflammation-related molecules TNF-α, IL-1β, IL-6 levels usually caused by ischemia/reperfusion were significantly ameliorated by EGCG. EGCG also inhibited the upregulation of nuclear factor-kappa B/p65 (NF-κB/p65), and induction of cyclooxygenase 2 and inducible nitric oxide synthase. The present study indicates that EGCG may be a promising therapeutic agent for cerebral ischemia/reperfusion injury through attenuation of inflammation.

Rosiglitazone inhibits chlorpyrifos-induced apoptosis via modulation of the oxidative stress and inflammatory response in SH-SY5Y cells

Oxidative stress can lead to expression of inflammatory transcription factors, which are important regulatory elements in the induction of inflammatory responses. One of the transcription factors, nuclear transcription factor kappa-B (NF-κB) plays a significant role in the inflammation regulatory process. Inflammatory cell death has been implicated in neuronal cell death in some neurodegenerative disorders such as Parkinson's disease (PD). In this study, we investigated the molecular mechanisms underlying apoptosis initiated by chlorpyrifos (CPF)-mediated oxidative stress. Based on the cytotoxic mechanism of CPF, we examined the neuroprotective effects of rosiglitazone (RGZ), a peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist, against CPF-induced neuronal cell death. The treatment of SH-SY5Y cells with CPF induced oxidative stress. In addition, CPF activated the p38, JNK and ERK mitogen-activated protein kinases (MAPKs), and induced increases in the inflammatory genes such as COX-2 and TNF-α. CPF also induced nuclear translocation of NF-κB and inhibitors of NF-κB abolished the CPF-induced COX-2 expression. Pretreatment with RGZ significantly reduced ROS generation and enhanced HO-1 expression in CPF-exposed cells. RGZ blocked the activation of both p38 and JNK signaling, while ERK activation was strengthened. RGZ also attenuated CPF-induced cell death through the reduction of NF-κB-mediated proinflammatory factors. Results from this study suggest that RGZ may exert an anti-apoptotic effect against CPF-induced cytotoxicity by attenuation of oxidative stress as well as inhibition of the inflammatory cascade via inactivation of signaling by p38 and JNK, and NF-κB.

The effects of hematopoietic growth factors on neurite outgrowth

Stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) are initially discovered as the essential hematopoietic growth factors regulating bone marrow stem cell proliferation and differentiation, and SCF in combination with G-CSF (SCF+G-CSF) has synergistic effects on bone marrow stem cell mobilization. In this study we have determined the effect of SCF and G-CSF on neurite outgrowth in rat cortical neurons. Using molecular and cellular biology and live cell imaging approaches, we have revealed that receptors for SCF and G-CSF are expressed on the growth core of cortical neurons, and that SCF+G-CSF synergistically enhances neurite extension through PI3K/AKT and NFκB signaling pathways. Moreover, SCF+G-CSF induces much greater NFκB activation, NFκB transcriptional binding and brain-derived neurotrophic factor (BDNF) production than SCF or G-CSF alone. In addition, we have also observed that BDNF, the target gene of NFκB, is required for SCF+G-CSF-induced neurite outgrowth. These data suggest that SCF+G-CSF has synergistic effects to promote neurite growth. This study provides new insights into the contribution of hematopoietic growth factors in neuronal plasticity.

Nuclear factor-κB/Bcl-XL pathway is involved in the protective effect of hydrogen-rich saline on the brain following experimental subarachnoid hemorrhage in rabbits

Early brain injury (EBI), a significant contributor to poor outcome after subarachnoid hemorrhage (SAH), is intimately associated with neuronal apoptosis. Recently, the protective role of hydrogen (H2 ) in the brain has been widely studied, but the underlying mechanism remains elusive. Numerous studies have shown nuclear factor-κB (NF-κB) as a crucial survival pathway in neurons. Here we investigated the role of H2 in EBI following SAH, focusing on the NF-κB pathway. A double blood injection model was used to produce experimental SAH, and H2 -rich saline was injected intraperitoneally. NF-κB activity within the occipital cortex was measured. Immunofluorescence was performed to demonstrate the activation of NF-κB; Bcl-xL and cleaved caspase-3 were determined via Western blot. Gene expression of Bcl-xL was detected by real-time PCR, and TUNEL and Nissl staining were performed to illustrate brain injury in the occipital cortex. SAH induced a significant increase of cleaved caspase-3. Correspondingly, TUNEL staining demonstrated obvious neuronal apoptosis following SAH. In contrast, H2 treatment markedly increased NF-κB activity and the expression of Bcl-xL and decreased the level of cleaved caspase-3. Additionally, H2 treatment significantly reduced post-SAH neuronal apoptosis. The current study shows that H2 treatment alleviates EBI in the rabbits following SAH and that NF-κB/Bcl-xL pathway is involved in the protective role of H2 .

Cathepsin X promotes 6-hydroxydopamine-induced apoptosis of PC12 and SH-SY5Y cells

The cysteine carboxypeptidase cathepsin X is an important player in degenerative processes under normal ageing and pathological conditions. In the present study, we investigated the potential role of cathepsin X in 6-hydroxydopamine (6-OHDA)-induced toxicity in the pheochromocytoma cell line PC12 and neuroblastoma cell line SH-SY5Y. Cells exposed to 6-OHDA demonstrated alterations in the protein level of cathepsin X and activity of cathepsin X. Downregulation of cathepsin X expression by siRNA attenuated the neuronal death caused by 6-OHDA. Treatment with specific cathepsin X inhibitor AMS36 protected cells against 6-OHDA mediated cytotoxicity, resulting in reduced cell death and apoptosis. Furthermore, AMS36 reversed 6-OHDA-induced loss of tyrosine hydroxylase and attenuated 6-OHDA-induced activation of caspase-3, triggering apoptosis, intracellular generation of reactive oxygen species and mitochondrial dysfunction, including the release of cytochrome c and an imbalanced Bax/Bcl-2 ratio. Moreover, AMS36 interfered with NF-κB activation by blocking degradation of IκBα, preventing NF-κB translocation to the nucleus. Our data provide the first evidence that inhibition of cathepsin X protects both, PC12 and SH-SY5Y cells against 6-OHDA toxicity and indicate that cathepsin X may be responsible for dopamine neuron death, involved in the pathogenic cascade event for the neurodegenerative disorders, such as Parkinson's disease.

Ras and rheb signaling in survival and cell death

One of the most obvious hallmarks of cancer is uncontrolled proliferation of cells partly due to independence of growth factor supply. A major component of mitogenic signaling is Ras, a small GTPase. It was the first identified human protooncogene and is known since more than three decades to promote cellular proliferation and growth. Ras was shown to support growth factor-independent survival during development and to protect from chemical or mechanical lesion-induced neuronal degeneration in postmitotic neurons. In contrast, for specific patho-physiological cases and cellular systems it has been shown that Ras may also promote cell death. Proteins from the Ras association family (Rassf, especially Rassf1 and Rassf5) are tumor suppressors that are activated by Ras-GTP, triggering apoptosis via e.g., activation of mammalian sterile 20-like (MST1) kinase. In contrast to Ras, their expression is suppressed in many types of tumours, which makes Rassf proteins an exciting model for understanding the divergent effects of Ras activity. It seems likely that the outcome of Ras signaling depends on the balance between the activation of its various downstream effectors, thus determining cellular fate towards either proliferation or apoptosis. Ras homologue enriched in brain (Rheb) is a protein from the Ras superfamily that is also known to promote proliferation, growth, and regeneration through the mammalian target of rapamycin (mTor) pathway. However, recent evidences indicate that the Rheb-mTor pathway may switch its function from a pro-growth into a cell death pathway, depending on the cellular situation. In contrast to Ras signaling, for Rheb, the cellular context is likely to modulate the whole Rheb-mTor pathway towards cellular death or survival, respectively.

P268S in NOD2 associates with susceptibility to Parkinson's disease in Chinese population

Background

The cause of almost all cases of Parkinson’s disease (PD) remains unknown. Recent years have seen an explosion in the rate of discovery of genetic defects linked to PD. Different racial and geographical populations may have different distributions of genetic variants.

Methods

In the current study, we screened the following genetic variants, including some rare mutations and single nucleotide polymorphisms (SNPs), in a pedigree and cases-controls. To best of our knowledge, we first screened these variants known to be associated with neurodegeneration disease, E46K (rs104893875) in SNCA, A1442P in LRRK2, IVS9 in PARK2, A350V in SLC41A1, P268S (rs2066842), R702W (rs2066844), G908R (rs2066845), 1007fs (rs2066847) in NOD2 and G2385R (rs34778348) in LRRK2 from southern China population. Genotyping was performed by jointly using primers overlapping polymerase chain reaction (PCR) site-directed mutagenesis, restriction fragment length polymorphism (RFLP), and capillary electrophoresis (CE).

Results

We didn’t discover above 9 variants in the family members of the pedigree. Furthermore, of 237 patients with sporadic Parkinson’s disease and 190 controls, no heterozygosity or homozygosity were found from E46K, A1442P, A350V, R702W, G908R, or 1007fs but heterozygosity onto G2385R, IVS9, and P268S. No significant difference between cases and controls was found in both allele frequency (P = 0.572) and genotype frequency (P = 0.348) of IVS9. However, significant differences in genotype frequency (P = 0.009) of G2385R were consistent with prior observation. Eight patients with Parkinson’s disease (2 women and 6 men are over the age of 50 years at onset of PD) carried the P268S heterozygous variation in NOD2. There was no heterozygosity or homozygosity of P268S in the controls. Genotype frequency of P268S (P = 0.0450) had significant differences.

Conclusions

Our results suggested that the P268S variant in NOD2 might be a risk factor for susceptibility to sporadic Parkinson’s disease in Chinese populations. It also implied that the inflammatory response may play a role in PD.

NF-κB signaling pathways: role in nervous system physiology and pathology

Intracellular pathways related to cell survival regulate neuronal physiology during development and neurodegenerative disorders. One of the pathways that have recently emerged with an important role in these processes is nuclear factor-κB (NF-κB). The activity of this pathway leads to the nuclear translocation of the NF-κB transcription factors and the regulation of anti-apoptotic gene expression. Different stimuli can activate the pathway through different intracellular cascades (canonical, non-canonical, and atypical), contributing to the translocation of specific dimers of the NF-κB transcription factors, and each of these dimers can regulate the transcription of different genes. Recent studies have shown that the activation of this pathway regulates opposite responses such as cell survival or neuronal degeneration. These apparent contradictory effects depend on conditions such as the pathway stimuli, the origin of the cells, or the cellular context. In the present review, the authors summarize these findings and discuss their significance with respect to survival or death in the nervous system.

A novel dual signaling axis for NSP 5a3a induced apoptosis in head and neck carcinoma

NSP 5a3a is a novel structural protein found to be over-expressed in certain cancer cell lines in-vitro such as Hela, Saos-2, and MCF-7 while barely detectable levels in normal body tissues except for Testis. This particular isoform has been known to interact with cyto- nuclear proteins B23, known to be involved in multi-faceted cellular processes such as cell division, apoptosis, ribosome biogenesis, and rRNA processing, as well as with hnRNP-L, known to be involved with RNA metabolism and rRNA processing. A previous preliminary investigation of NSP 5a3a as a potential target in Head and Neck Carcinoma revealed a novel p73 dependent mechanism through which NSP 5a3a induced apoptosis in Head and Neck cell lines when over-expressed in-vitro. Our present investigation further elucidated a novel dual axis signaling point by which NSP 5a3a induces apoptosis in Head and Neck cell line HN30 through p73-DAXX and TRAF2-TRADD. Interestingly, this novel mechanism appears independent of canonical caspases involved in the intrinsic mitochondrial pathway as well as those in the death receptor pathway thru TRAF2 and TRADD.

Neuronal NF-κB ablation does not influence neuro-axonal degeneration in experimental autoimmune demyelination

Neuro-axonal damage is a major hallmark of multiple sclerosis (MS). To date, not much is known on the underlying mechanisms of neuronal degeneration. In disease model myelin oligodendrocyte glycoprotein induced experimental autoimmune encephalomyelitis (MOG-EAE), there is a significant loss of alpha motorneurons in the cervical as well as thoracic and lumbar spinal cord. We further investigate the role of activated NF-κB for neuronal damage in a conditional ablation mouse model. A calcium calmodulin kinase II promoter-driven tetracycline transactivator is employed to regulate the expression of a human transdominant negative IκB-alpha mutant in the basal forebrain and selected neuronal subpopulations in the cerebellum and spinal cord including cerebellar Purkinje cells and spinal cord alpha motorneurons. In these mice with conditional neuronal NF-κB ablation, the clinical course of MOG-EAE, parameters of inflammation and axonal densities in the spinal cord white and grey matter as well as numbers of alpha motorneurons are not different to littermate controls. In conclusion, neuronal NF-κB ablation does not modulate neurodegeneration in autoimmune demyelination.

Mitochondrial neuronal uncoupling proteins: a target for potential disease-modification in Parkinson's disease

This review gives a brief insight into the role of mitochondrial dysfunction and oxidative stress in the converging pathogenic processes involved in Parkinson's disease (PD). Mitochondria provide cellular energy in the form of ATP via oxidative phosphorylation, but as an integral part of this process, superoxides and other reactive oxygen species are also produced. Excessive free radical production contributes to oxidative stress. Cells have evolved to handle such stress via various endogenous anti-oxidant proteins. One such family of proteins is the mitochondrial uncoupling proteins (UCPs), which are anion carriers located in the mitochondrial inner membrane. There are five known homologues (UCP1 to 5), of which UCP4 and 5 are predominantly expressed in neural cells. In a series of previous publications, we have shown how these neuronal UCPs respond to 1-methyl-4-phenylpyridinium (MPP+; toxic metabolite of MPTP) and dopamine-induced toxicity to alleviate neuronal cell death by preserving ATP levels and mitochondrial membrane potential, and reducing oxidative stress. We also showed how their expression can be influenced by nuclear factor kappa-B (NF-κB) signaling pathway specifically in UCP4. Furthermore, we previously reported an interesting link between PD and metabolic processes through the protective effects of leptin (hormone produced by adipocytes) acting via UCP2 against MPP+-induced toxicity. There is increasing evidence that these endogenous neuronal UCPs can play a vital role to protect neurons against various pathogenic stresses including those associated with PD. Their expression, which can be induced, may well be a potential therapeutic target for various drugs to alleviate the harmful effects of pathogenic processes in PD and hence modify the progression of this disease.

Preconditioning with a novel metallopharmaceutical NO donor in anesthetized rats subjected to brain ischemia/reperfusion

Rut-bpy is a novel nitrosyl-ruthenium complex releasing NO into the vascular system. We evaluated the effect of Rut-bpy (100 mg/kg) on a rat model of brain stroke. Forty rats were assigned to four groups (Saline solution [SS], Rut-bpy, SS+ischemia-reperfusion [SS+I/R] and Rut-bpy+ischemia-reperfusion [Rut-bpy+I/R]) with their mean arterial pressure (MAP) continuously monitored. The groups were submitted (SS+I/R and Rut-bpy+I/R) or not (SS and Rut-bpy) to incomplete global brain ischemia by occlusion of the common bilateral carotid arteries during 30 min followed by reperfusion for further 60 min. Thirty minutes before ischemia, rats were treated pairwise by intraperitoneal injection of saline solution or Rut-bpy. At the end of experiments, brain was removed for triphenyltetrazolium chloride staining in order to quantify the total ischemic area. In a subset of rats, hippocampus was obtained for histopathology scoring, nitrate and nitrite measurements, immunostaining and western blotting of the nuclear factor- κB (NF-κB). Rut-bpy pre-treatment decreased MAP variations during the transition from brain ischemia to reperfusion and decreased the fractional injury area. Rut-bpy pre-treatment reduced NF-κB hippocampal immunostaining and protein expression with improved histopathology scoring as compared to the untreated operated control. In conclusion, Rut-bpy improved the total brain infarction area and hippocampal neuronal viability in part by inhibiting NF-κB signaling and helped to stabilize the blood pressure during the transition from ischemia to reperfusion.

Iron overload triggers redox-sensitive signals in human IMR-32 neuroblastoma cells

Excessive neuronal iron has been proposed to contribute to the pathology of several neurodegenerative diseases including Alzheimer's and Parkinson's diseases. This work characterized human neuroblastoma IMR-32 cells exposure to ferric ammonium citrate (FAC) as a model of neuronal iron overload and neurodegeneration. The consequences of FAC treatment on neuronal oxidative stress and on the modulation of the oxidant-sensitive transcription factors AP-1 and NF-κB were investigated. Incubation with FAC (150μM) resulted in a time (3-72h)-dependent increase in cellular iron content, and was associated with cell oxidant increase. FAC caused a time-dependent (3-48h) increase in nuclear AP-1- and NF-κB-DNA binding. This was associated with the upstream activation of the mitogen activated kinases ERK1/2, p38 and JNK and of IκBα phosphorylation and degradation. After 72h incubation with FAC, cell viability was 40% lower than in controls. Iron overload caused apoptotic cell death. After 48-72h of incubation with FAC, caspase 3 activity was increased, and chromatin condensation and nuclear fragmentation were observed. In summary, the exposure of IMR-32 cells to FAC is associated with increased oxidant cell levels, activation of redox-sensitive signals, and apoptosis.

Functional aspects of redox control during neuroinflammation

Neuroinflammation is a CNS reaction to injury in which some severe pathologies, regardless of their origin, converge. The phenomenon emphasizes crosstalk between neurons and glia and reveals a complex interaction with oxidizing agents through redox sensors localized in enzymes, receptors, and transcription factors. When oxidizing pressures cause reversible molecular changes, such as minimal or transitory proinflammatory cytokine overproduction, redox couples provide a means of translating the presence of reactive oxygen or nitrogen species into useful signals in the cell. Additionally, thiol-based redox sensors convey information about localized changes in redox potential induced by physiologic or pathologic situations. They are susceptible to oxidative changes and become key events during neuroinflammation, altering the course of a signaling response or the behavior of specific transcription factors. When oxidative stress augments the pressure on the intracellular environment, the effective reduction potential of redox pairs diminishes, and cell signaling shifts toward proinflammatory and proapoptotic signals, creating a vicious cycle between oxidative stress and neuroinflammation. In addition, electrophilic compounds derived from the oxidative cascade react with key protein thiols and interfere with redox signaling. This article reviews the relevant functional aspects of redox control during the neuroinflammatory process.

Neuroprotective herbs and foods from different traditional medicines and diets

Plant secondary metabolites include an array of bioactive constituents form both medicinal and food plants able to improve human health. The exposure to these phytochemicals, including phenylpropanoids, isoprenoids and alkaloids, through correct dietary habits, may promote health benefits, protecting against the chronic degenerative disorders mainly seen in Western industrialized countries, such as cancer, cardiovascular and neurodegenerative diseases. In this review, we briefly deal with some plant foods and herbs of traditional medicines and diets, focusing on their neuroprotective active components. Because oxidative stress and neuroinflammation resulting from neuroglial activation, at the level of neurons, microglial cells and astrocytes, are key factors in the etiopathogenesis of both neurodegenerative and neurological diseases, emphasis will be placed on the antioxidant and anti-inflammatory activity exerted by specific molecules present in food plants or in remedies prescribed by herbal medicines.

NF-kappaB in the nervous system

The transcription factor NF-kappaB has diverse functions in the nervous system, depending on the cellular context. NF-kappaB is constitutively activated in glutamatergic neurons. Knockout of p65 or inhibition of neuronal NF-kappaB by super-repressor IkappaB resulted in the loss of neuroprotection and defects in learning and memory. Similarly, p50-/- mice have a lower learning ability and are sensitive to neurotoxins. Activated NF-kappaB can be transported retrogradely from activated synapses to the nucleus to translate short-term processes to long-term changes such as axon growth, which is important for long-term memory. In glia, NF-kappaB is inducible and regulates inflammatory processes that exacerbate diseases such as autoimmune encephalomyelitis, ischemia, and Alzheimer's disease. In summary, inhibition of NF-kappaB in glia might ameliorate disease, whereas activation in neurons might enhance memory. This review focuses on results produced by the analysis of genetic models.

Protection by tetrahydroxystilbene glucoside against cerebral ischemia: involvement of JNK, SIRT1, and NF-kappaB pathways and inhibition of intracellular ROS/RNS generation

Many natural polyphenolic compounds have been shown to attenuate reactive oxygen/nitrogen species (ROS/RNS) formation and protect against ischemia/reperfusion injury both in vitro and in vivo. 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (TSG), an active component of the rhizome extract from Polygonum multiflorum, exhibits antioxidative and anti-inflammatory effects. Here, we used an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD-R) and an in vivo ischemic model of middle cerebral artery occlusion (MCAO) to investigate the neuroprotective effects of TSG on ischemia/reperfusion brain injury and the related mechanisms. We demonstrated that OGD-R-induced neuronal injury, intracellular ROS generation, and mitochondrial membrane potential dissipation were reversed by TSG. The elevation of H2O2-induced [Ca2+]i was also attenuated by TSG. Inhibition of the c-Jun N-terminal kinase (JNK) and Bcl-2 family-related apoptotic signaling pathway was involved in the neuroprotection afforded by TSG. Meanwhile, TSG inhibited iNOS mRNA expression induced by OGD-R, which may be mediated by the activation of SIRT1 and inhibition of NF-kappaB activation. In vivo studies further demonstrated that TSG significantly reduced the brain infarct volume and the number of positive cells by TUNEL staining in the cerebral cortex compared to the MCAO group. Our study indicates that TSG protects against cerebral ischemia/reperfusion injury through multifunctional cytoprotective pathways.

Thermal killing of human colon cancer cells is associated with the loss of eukaryotic initiation factor 5A

Heat-induced cell death appears to be a cell-specific event. Chronic heat stress was lethal to human colon cancer cells (Caco-2, HT29, and HCT116), but not to normal diploid fibroblasts and other cancer cells (BJ-T, WI38, HeLa, ovarian 2008, WI38VA). Acute heat stress (45-51 degrees C, 30 min) caused cell death of colon cancer cells during recovery at physiological temperature. Thermal killing of Caco-2 cells was not mediated via oxidative stress since Caco-2 cells were much more resistant than HeLa and other cancer cells to H(2)O(2)-induced cell death. Acute heat stress caused a striking loss of eukaryotic initiation factor 5A (eIF5A) in colon cancer cells, but not in HeLa and other normal or transformed human fibroblasts. The heat-induced loss of eIF5A is likely to be due to changes in the protein stability. The half-life of eIF5A was changed from >20 h to less than 30 min during the acute heat stress. Sequence analysis of the eIF5A gene from Caco-2 and HeLa cells did not reveal any difference, suggesting that the change in stability in Caco-2 cells was not due to any eIF5A mutation. Pretreatment of cells with protease inhibitors such as phenylmethyl sulfonyl fluoride (PMSF) partially blocked the heat-induced loss of eIF5A and prevented heat-induced cell death. In light of the essential role of eIF5A in cell survival and proliferation, our results suggest that the stability of eIF5A may have an important role in determining the fate of the particular cell type after severe heat stress.

c-Rel, an NF-kappaB family transcription factor, is required for hippocampal long-term synaptic plasticity and memory formation

Transcription is a critical component for consolidation of long-term memory. However, relatively few transcriptional mechanisms have been identified for the regulation of gene expression in memory formation. In the current study, we investigated the activity of one specific member of the NF-kappaB transcription factor family, c-Rel, during memory consolidation. We found that contextual fear conditioning elicited a time-dependent increase in nuclear c-Rel levels in area CA1 and DG of hippocampus. These results suggest that c-rel is active in regulating transcription during memory consolidation. To identify the functional role of c-Rel in memory formation, we characterized c-rel(-/-) mice in several behavioral tasks. c-rel(-/-) mice displayed significant deficits in freezing behavior 24 h after training for contextual fear conditioning but showed normal freezing behavior in cued fear conditioning and in short-term contextual fear conditioning. In a novel object recognition test, wild-type littermate mice exhibited a significant preference for a novel object, but c-rel(-/-) mice did not. These results indicate that c-rel(-/-) mice have impaired hippocampus-dependent memory formation. To investigate the role of c-Rel in long-term synaptic plasticity, baseline synaptic transmission and long-term potentiation (LTP) at Schaffer collateral synapses in c-rel(-/-) mice was assessed. c-rel(-/-) slices had normal baseline synaptic transmission but exhibited significantly less LTP than did wild-type littermate slices. Together, our results demonstrate that c-Rel is necessary for long-term synaptic potentiation in vitro and hippocampus-dependent memory formation in vivo.

Effects of different concentrations of oxygen-ozone on rats' astrocytes in vitro

Although the widespread use of the oxygen-ozone in pain management, there is currently no consensus on its mechanisms of action and nearly no report for its action on nervous cells. Accordingly, the present study was designed to assess the effects of oxygen-ozone on astrocytes. Astrocytes were cultured in vitro through methods of trypsinization, different-speed cultivation and passaging to purify, then seeded into 24 well plates and divided to one of four groups (n=7) to receive the following treatments: respectively added 400 microl complete medium (CM) after effects of 20 microg/ml oxygen-ozone (Group O-20), 40 microg/ml oxygen-ozone (Group O-40), 60 microg/ml oxygen-ozone (Group O-60); without intervention (Group C). After incubation of 2 h or 4 h, cell morphology was observed and endocellular superoxide dismutase (SOD), endocellular malondialdehyde (MDA), lactate dehydrogenase (LDH) leaking ratio, and dead cells' percentage were detected. The results showed cell damage in Group O-60. As compared with Group C, endocellular SOD increased in all groups, MDA at 2 h increased in Groups O-40 and O-60 and MDA at 4 h decreased in Groups O-20 and O-40; LDH leaking ratio at 2 h in Group O-20 and those at 2 and 4 h in Group O-40 decreased, while LDH leaking ratio at 4 h increased and dead cells' percentage in Group O-60 increased. We conclude that in short time (2 and 4 h), oxygen-ozone of 60 microg/ml showed a damaging role on astrocytes in vitro, while oxygen-ozone of 20 and 40 microg/ml did not show damaging role obviously.

Paraquat induces apoptosis in human lymphocytes: protective and rescue effects of glucose, cannabinoids and insulin-like growth factor-1

In order to establish causal or protective treatments for Parkinson's disease (PD), it is necessary to identify the cascade of deleterious events that lead to the dysfunction and death of dopaminergic neurons. Paraquat (PQ) is a pesticide used as xenobiotic compound to model PD. However, the mechanism(s) of PQ-induced cell death and the mechanism(s) of cytoprotection in a single cell model are still unknown. In this study, lymphocytes were treated with (0.1-1 mM) PQ. Apoptotic morphology was assessed with acridine orange/ethidium bromide staining. Further evaluation included (i) superoxide radicals, reflected by nitroblue tetrazolium reduction to formazan, (ii) the production of hydrogen peroxide, reflected by rhodamine-positive fluorescent cells, (iii) the generation of hydroxyl radicals, reflected by dimethylsulfoxide and melatonin ( radical)OH scavengers, (iv) activation and/or translocation of NF-kappaB, p53 and c-Jun transcription factors showed by immunocytochemical staining, and by ammonium pyrrolidinedithiocarbamate, pifithrin-alpha and SP600125 inhibition and (V) caspase-3 activation, reflected by caspase Ac-DEVD-cho inhibition. To elucidate the mechanism of cytoprotection, lymphocytes were treated with PQ in the presence of cannabinoids, insulin-like growth factor-1 and glucose. We provide evidence that PQ induces apoptosis in lymphocytes in a concentration- and time-dependent fashion by an oxidative stress mechanism involving O(2)( radical - ), H(2)O(2)/(( radical)OH) generation, simultaneous activation of NF-kappaB/p53/c-Jun transcription factors, mitochondrial depolarization and caspase-3 activation leading to morphological apoptosis. Moreover, dying lymphocytes are protected and rescued from PQ noxious stimuli by direct antioxidant effect by cannabinoids, receptor mediated signaling by IGF-1, and/or energetic protection by glucose. It is concluded that PQ-induced apoptosis in lymphocytes by a mechanism involving reactive oxygen species generation, mitochondrial dysfunction, transcriptional factors and caspase-3 activation. However, this cell death routine can be reversed by the action of cannabinoids, IGF-1 and glucose. These data may provide innovating therapeutic strategies to intervene environmentally or genetically susceptible PD population to oxidative stress.

Hormesis: a promising strategy to sustain endogenous neuronal survival pathways against neurodegenerative disorders

The brain developed adaptive mechanisms in the face of changing environments and stresses imposed on the nervous system. The addition of glutamate as the major excitatory amino acid neurotransmitter to the brain's complement of amino acids and peptides dictated a coordinated transcriptional and translational program to meet the demands of excitatory neurotransmission. One such program is the ability of neurons to sustain and maintain their survival given the nature of glutamate-mediated receptor activation. The unique development of endogenous neuronal pathways activated by glutamate receptors transformed neurons and allowed them to survive under conditions of high energy demands. These same endogenous survival pathways also mediate plastic responses to meet another demand of the brain, adaptation. An endogenous protein that plays a central role in glutamate receptor-mediated survival pathways is brain-derived neurotrophic factor (BDNF). Intermittent but frequent synaptic ionotropic glutamate receptor activation ensures neuronal survival through a BDNF autocrine loop. In sharp contrast, overactivation of ionotropic glutamate receptors leads to neuronal cell death. Thus, innovative strategies that induce endogenous neuronal survival pathways through low-level activation of ionotropic glutamate receptors or those that bypass receptor activation but upregulate endogenous survival pathways may not only prevent neurodegenerative disorders that involve glutamate as a final common pathway that kills neurons, but may also provide treatment alternatives critical for neurons to survive stressful conditions such as stroke, status epilepticus and hypoglycemic-induced neuronal cell death.

Neural stem cells, inflammation and NF-kappaB: basic principle of maintenance and repair or origin of brain tumours?

Several recent reports suggest that inflammatory signals play a decisive role in the self-renewal, migration and differentiation of multipotent neural stem cells (NSCs). NSCs are believed to be able to ameliorate the symptoms of several brain pathologies through proliferation, migration into the area of the lesion and either differentiation into the appropriate cell type or secretion of anti-inflammatory cytokines. Although NSCs have beneficial roles, current evidence indicates that brain tumours, such as astrogliomas or ependymomas are also caused by tumour-initiating cells with stem-like properties. However, little is known about the cellular and molecular processes potentially generating tumours from NSCs. Most pro-inflammatory conditions are considered to activate the transcription factor NF-kappaB in various cell types. Strong inductive effects of NF-kappaB on proliferation and migration of NSCs have been described. Moreover, NF-kappaB is constitutively active in most tumour cells described so far. Chronic inflammation is also known to initiate cancer. Thus, NF-kappaB might provide a novel mechanistic link between chronic inflammation, stem cells and cancer. This review discusses the apparently ambivalent role of NF-kappaB: physiological maintenance and repair of the brain via NSCs, and a potential role in tumour initiation. Furthermore, it reveals a possible mechanism of brain tumour formation based on inflammation and NF-kappaB activity in NSCs.

Differential regulation of Mn-superoxide dismutase in neurons and astroglia by HIV-1 gp120: Implications for HIV-associated dementia

HIV-associated dementia, like several other neurodegenerative diseases, is characterized by selective degeneration of neurons amidst survival of glial cells like astroglia. The molecular basis of such selective susceptibility within the same milieu remains largely unknown. Neurons are rarely infected by the virus. However, they are vulnerable to viral products, like HIV-1 coat protein gp120. Interestingly, gp120 induced oxidative stress in neurons, but not in astroglia. This led us to postulate that astroglia were armed with a more efficient antioxidant system than neurons. Here, we report that the constitutive level of MnSOD (SOD2), the major cellular antioxidant enzyme, is significantly higher in astroglia than in neurons. Furthermore, gp120 treatment enhanced MnSOD levels in astroglia but decreased the same in neurons. This increase in astroglial MnSOD was dependent on NF-kappaB, the crucial transcription factor required for sod2 gene transcription. Blocking NF-kappaB with p65-antisense, p65-si-RNA, or a specific inhibitor, NBD peptide, led to reduced MnSOD levels and enhanced vulnerability of astroglia to gp120. Additionally, neurons were found to have a lower constitutive level of NF-kappaB p65 than astrocytes. Overexpression of p65 increased the level of MnSOD in neurons. This, in turn, elicited greater neuronal resistance to gp120. Taken together, our study suggests that astroglia manifest a higher threshold for gp120-induced lethality than neurons due to greater MnSOD availability, which is demonstrated due to greater level of NF-kappaB p65.

NF-κB contributes to 6-hydroxydopamine-induced apoptosis of nigral dopaminergic neurons through p53

To evaluate the contribution of NF-kappaB and the NF-kappaB target gene p53 to nigral dopaminergic neuron degeneration in rodent models of Parkinson's disease, time-course of dopaminergic neuron loss as well as changes in the expression of some NF-kappaB-regulated proapoptotic proteins were assayed after unilateral infusion of 6-hydroxydopamine into rat medial forebrain bundle. Substantial loss of tyrosine hydroxylase immunoreactivity in nigral was observed 24 h after 6-hydroxydopamine treatment. The degenerative processes began 12 h after 6-hydroxydopamine administration as evidenced by a positive silver staining. Apoptotic death of dopaminergic neurons was suggested by the appearance of TUNEL-positive nuclei in substantia nigra and internucleosomal DNA fragmentation as detected by agarose gel electrophoresis. NF-kappaB activation in dopaminergic neurons as revealed by immunohistochemistry and electrophoresis mobility shift assay, began at 12 h after 6-hydroxydopamine administration. Levels of c-Myc and p53 immunoreactivities increased after 6-hydroxydopamine treatment, mainly in dopaminergic neurons as indicated by co-localization with tyrosine hydroxylase immunoreactivity. Blockade of NF-kappaB nuclear translocation with recombinant cell-permeable peptide NF-kappaB SN50 inhibited NF-kappaB nuclear translocation and p53 induction. SN50 and the p53 antagonist pifithrin-alpha significantly reduced nigral dopaminergic neuron degeneration. These results suggest that NF-kappaB activation contributes, at least in part, to oxidative stress-induced degeneration of dopaminergic neurons through a NF-kappaB-dependent p53-signaling pathway.

Bim and Noxa are candidates to mediate the deleterious effect of the NF-kappa B subunit RelA in cerebral ischemia

The transcription factor nuclear factor kappaB (NF-kappaB) is well known for its antiapoptotic action. However, in some disorders, such as cerebral ischemia, a proapoptotic function of NF-kappaB has been demonstrated. To analyze which subunit of NF-kappaB is functional in cerebral ischemia, we induced focal cerebral ischemia in mice with a germline deletion of the p52 or c-Rel gene or with a conditional deletion of RelA in the brain. Only RelA deficiency reduced infarct size. Interestingly, expression of the proapoptotic BH3 (Bcl-2 homology domain 3)-only genes Bim and Noxa in cerebral ischemia depended on RelA and the upstream kinase IKK (IkappaB kinase). RelA stimulated Bim and Noxa gene transcription in primary cortical neurons and bound to the promoter of both genes. Thus, the deleterious function in cerebral ischemia is specific for the NF-kappaB subunit RelA and may be mediated through Bim and Noxa.

CARD15 variants in patients with sporadic Parkinson's disease

Recent reports have proven the importance of genetic factors and inflammation in the pathogenesis of sporadic Parkinson's disease (PD). In the current study, the frequency of CARD15/NOD2 gene variants (R702W, G908R, L1007fs), previously associated with Crohn's disease--a common inflammatory bowel disease, have been examined in a group of 308 sporadic PD patients and 220 healthy controls. Significantly higher frequency of total CARD15 variant alleles in PD patients (13.0%) compared to the controls (8.0%, p<0.02) was observed. 24.0% of PD patients carried at least one CARD15 variant allele compared to 15.5% of healthy controls (p<0.02, OR=1.73). The results of the study suggest, that the polymorphism in CARD15/NOD2 gene may be a risk factor for sporadic PD development, and support the concept of inflammatory pathogenesis of PD.

NF-kappaB functions in the nervous system: from development to disease

The transcription factor nuclear factor-kappaB (NF-kappaB) is an ubiquitously expressed dimeric molecule with post-translationally regulated activity. Its role in the immune system and host defense has been well characterized over the last two decades. In contrast, our understanding of the function of this transcription factor in the nervous system (NS) is only emerging. Given their cytoplasmic retention and nuclear translocation upon stimulus, NF-kappaB members are likely to exert an important role in transduction of signals from synaptic terminals to nucleus, to initiate transcriptional responses. This report describes recent findings deciphering the diverse functions of NF-kappaB in NS development and activity, which range from the control of cell growth, survival and inflammatory response to synaptic plasticity, behavior and cognition. Particular attention is given to the specific roles of NF-kappaB in the various cells of the NS, e.g. neurons and glia. Current knowledge of the contribution of NF-kappaB to several neurodegenerative disorders, such as Alzheimer's, Parkinson's and Huntington's diseases is also summarized.

Emerging role of polyphenolic compounds in the treatment of neurodegenerative diseases: a review of their intracellular targets

Aging is the major risk factor for neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. A large body of evidence indicates that oxidative stress is involved in the pathophysiology of these diseases. Oxidative stress can induce neuronal damages, modulate intracellular signaling, ultimately leading to neuronal death by apoptosis or necrosis. Thus antioxidants have been studied for their effectiveness in reducing these deleterious effects and neuronal death in many in vitro and in vivo studies. Increasing number of studies demonstrated the efficacy of polyphenolic antioxidants from fruits and vegetables to reduce or to block neuronal death occurring in the pathophysiology of these disorders. These studies revealed that other mechanisms than the antioxidant activities could be involved in the neuroprotective effect of these phenolic compounds. We will review some of these mechanisms and particular emphasis will be given to polyphenolic compounds from green tea, the Ginkgo biloba extract EGb 761, blueberries extracts, wine components and curcumin.

Pro-apoptotic role of NF-kappaB: implications for cancer therapy

Nuclear factor-kappaB (NF-kappaB) is generally viewed as anti-apoptotic and oncogenic, leading to a quest for its inhibitors. However, recent evidence suggests that in some situations NF-kappaB may promote apoptosis. Depending on the specific cell type and the stimulus involved, NF-kappaB activation may lead to either anti- or pro-apoptotic response. Both these effects can be mediated by NF-kappaB in a context-dependent manner by selectively regulating its target genes. In this review, we discuss the evidence for NF-kappaB's pro-apoptotic role and explore the possible mechanisms behind it. We emphasize that rather than trying to inhibit NF-kappaB in cancer therapy, agents should be developed to unleash its pro-apoptotic ability.

Insulin-like growth factor-1 prevents Abeta[25-35]/(H2O2)- induced apoptosis in lymphocytes by reciprocal NF-kappaB activation and p53 inhibition via PI3K-dependent pathway

The role of insulin-like growth factor (IGF-1) as neural survival factor for the treatment of Alzheimer's disease has recently gained attention. The present study shows that IGF-1 protects lymphocytes from (10, 30 microM) Abeta[(25-35)] and (25, 50, 100 microM) H(2)O(2)-induced apoptosis through NF-kappaB activation and p53 down regulation involving the phosphoinositide 3-kinase (PI-3K)-dependent pathway as demonstrated by using either (25 microM) LY294002 (PI-3K inhibitor), (10 nM) ammonium pyrrolidinedithiocarbamate (PDTC; NF-kappaB inhibitor), 50 nM pifithrin-alpha (PFT; p53 inhibitor) or by using immunocytochemistry detection of NF-kappaB and p53 transcription factors activation. Importantly, IGF-1, PDTC and PFT were able to protect and rescue lymphocytes pre-exposed to 10 muM Abeta[(25-35)], even when the three compounds were added up-to 12 h post- Abeta[(25-35)] exposure. Altogether these results suggest that survival/rescue of lymphocytes from Abeta[(25-35)] toxicity is determined by p53 inactivation via IGF-1/ PI-3K pathway.

The NF-kappaB pathway mediates fenretinide-induced apoptosis in SH-SY5Y neuroblastoma cells

Fenretinide induces apoptosis in SH-SY5Y neuroblastoma cells via a signaling pathway involving the production of reactive oxygen species (ROS), 12-lipoxygenase activity and the induction of the GADD153 transcription factor. NF-kappa B is a key element of many cell signaling pathways and adopts a pro- or anti-apoptotic role in different cell types. Studies have suggested that NF-kappa B may play a pro-apoptotic role in SH-SY5Y cells, and in other cell types NF-kappa B activation may be linked to lipoxygenase activity. The aim of this study was to test the hypothesis that NF-kappa B activity mediates fenretinide-induced apoptosis in SH-SY5Y neuroblastoma cells. Using a dominant-negative construct for Ikappa Balpha stably transfected into SH-SY5Y cells, we show that apoptosis, but not the induction of ROS, in response to fenretinide was blocked by abrogation of NF-kappa B activity. In parental SH-SY5Y cells, fenretinide induced NF-kappa B activity and Ikappa Balpha phosphorylation. These results suggest that NF-kappa B activity links fenretinide-induced ROS to the induction of apoptosis in SH-SH5Y cells, and may be a target for the future development of drugs for neuroblastoma therapy.