NF-κB signalling regulates the growth of neural processes in the developing PNS and CNS

NF-κB Signaling Pathway in Rheumatoid Arthritis: Mechanisms and Therapeutic Potential

Rheumatoid arthritis (RA) is an autoimmune chronic inflammatory disease that imposes a heavy economic burden on patients and society. Bone and cartilage destruction is considered an important factor leading to RA, and inflammation, oxidative stress, and mitochondrial dysfunction are closely related to bone erosion and cartilage destruction in RA. Currently, there are limitations in the clinical treatment methods for RA, which urgently necessitates finding new effective treatments for patients. Nuclear transcription factor-κB (NF-κB) is a signaling transcription factor that is widely present in various cells. It plays an important role as a stress source in the cellular environment and regulates gene expression in processes such as immunity, inflammation, cell proliferation, and apoptosis. NF-κB has long been recognized as a pathogenic factor of RA, and its activation can exacerbate RA by promoting inflammation, oxidative stress, mitochondrial dysfunction, and bone destruction. Conversely, inhibiting the activity of the NF-κB pathway effectively inhibits these pathological processes, thereby alleviating RA. Therefore, NF-κB may be a potential therapeutic target for RA. This article describes the physiological structure of NF-κB and its important role in RA through the regulation of oxidative stress, inflammatory response, mitochondrial function, and bone destruction. Meanwhile, we also summarized the impact of NF-κB crosstalk with other signaling pathways on RA and the effect of related drugs or inhibitors targeting NF-κB on RA. The purpose of this article is to provide evidence for the role of NF-κB in RA and to emphasize its significant role in RA by elucidating the mechanisms, so as to provide a theoretical basis for targeting the NF-κB pathway as a treatment for RA.

Functional kinome profiling reveals brain protein kinase signaling pathways and gene networks altered by acute voluntary exercise in rats

Regular exercise confers numerous physical and mental health benefits, yet individual variability in exercise participation and outcomes is still poorly understood. Uncovering the neurobiological mechanisms governing exercise behavior is essential for promoting physical activity and developing targeted interventions for related disorders. While genetic studies have provided insights, they often cannot account for protein-level alterations, such as changes in kinase activity. Here, we employ protein kinase activity profiling to delineate brain protein kinase activity and signaling networks modulated by acute voluntary exercise in rats. Focusing on the dorsal striatum, which governs voluntary exercise, as well as the hippocampus, which is susceptible to modulation by physical activity, we aim to understand the molecular basis of exercise behavior. Utilizing high throughput kinome array profiling and advanced pathway analyses, we identified protein kinase signaling pathways implicated in regulating voluntary exercise. Pathway analysis using Gene Ontology (GO) revealed significant alterations in 155 GO terms in the dorsal striatum and 206 GO terms in the hippocampus. Changes in kinase activity were observed in the striatum and hippocampus between the exercise (voluntary wheel running, VWR) and sedentary control rats. In both regions, global serine-threonine kinase (STK) activity was decreased, while global phospho-tyrosine kinase (PTK) activity was increased in VWR rats compared to control rats. We also identified specific kinases altered in VWR rats, including the IKappaB Kinase (IKK) and protein kinase delta (PKD) families. C-terminal src Kinase (CSK), epidermal growth factor (EGFR), and vascular endothelial growth factor receptor (VEGFR) tyrosine kinase were also enriched. These findings suggest regional heterogeneity of kinase activity following voluntary exercise, emphasizing potential molecular mechanisms underlying exercise behavior. This exploratory study lays the groundwork for future investigations into the causality of variations in exercise outcomes among individuals and different sexes, as well as the development of targeted interventions to promote physical activity and combat associated chronic diseases.

Pathological tau activates inflammatory nuclear factor-kappa B (NF-κB) and pT181-Qβ vaccine attenuates NF-κB in PS19 tauopathy mice

Tau regulates neuronal integrity. In tauopathy, phosphorylated tau detaches from microtubules and aggregates, and is released into the extracellular space. Microglia are the first responders to the extracellular tau, a danger/damage-associated molecular pattern (DAMP), which can be cleared by proteostasis and activate innate immune response gene expression by nuclear factor-kappa B (NF-κB). However, longitudinal NF-κB activation in tauopathies and whether pathological tau (pTau) contributes to NF-κB activity is unknown. Here, we tau oligomers from human Alzheimer's disease brain (AD-TO) activate NF-κB in mouse microglia and macrophages reducing the IκBα via promoting its secretion in the extracellular space. NF-κB activity peaks at 9- and 11-months age in PS19Luc + and hTauLuc + mice, respectively. Reducing pTau via pharmacological (DOX), genetic ( Mapt -/- ) or antibody-mediated neutralization (immunization with pT181-Qβ vaccine) reduces NF-κB activity, and together suggest pTau is a driver of NF-κB and chronic neuroinflammation tauopathies.

Summary

Neuronal tau activates microglial NF-κB constitutively by secreting its inhibitor IκBα. NF-κB activation in PS19Luc + and hTauLuc + mice peaks at 9- and 11-months of age, respectively. Neutralizing pTau with pT181-Qβ vaccine (targeting phosphorylated threonine 181 tau) alleviates NF-κB activity in tauopathy mice.

Regulation of the microglial polarization for alleviating neuroinflammation in the pathogenesis and therapeutics of major depressive disorder

Major depressive disorder (MDD), as a multimodal neuropsychiatric and neurodegenerative illness with high prevalence and disability rates, has become a burden to world health and the economy that affects millions of individuals worldwide. Neuroinflammation, an atypical immune response occurring in the brain, is currently gaining more attention due to its association with MDD. Microglia, as immune sentinels, have a vital function in regulating neuroinflammatory reactions in the immune system of the central nervous system. From the perspective of steady-state branching states, they can transition phenotypes between two extremes, namely, M1 and M2 phenotypes are pro-inflammatory and anti-inflammatory, respectively. It has an intermediate transition state characterized by different transcriptional features and the release of inflammatory mediators. The timing regulation of inflammatory cytokine release is crucial for damage control and guiding microglia back to a steady state. The dysregulation can lead to exorbitant tissue injury and neuronal mortality, and targeting the cellular signaling pathway that serves as the regulatory basis for microglia is considered an essential pathway for treating MDD. However, the specific intervention targets and mechanisms of microglial activation pathways in neuroinflammation are still unclear. Therefore, the present review summarized and discussed various signaling pathways and effective intervention targets that trigger the activation of microglia from its branching state and emphasizes the mechanism of microglia-mediated neuroinflammation associated with MDD.

Gene Expression of Neurogenesis Related to Exercise Intensity in a Cerebral Infarction Rat Model

Regular exercise improves several functions, including cognition, in patients with stroke. However, the effect of regular exercise on neurogenesis related to cognition remains doubtful. We investigated the most effective exercise intensity for functional recovery after stroke using RNA sequencing following regular treadmill exercise. Photothrombotic cerebral infarction was conducted for 10-week-old male Sprague-Dawley rats (n = 36). A Morris water maze (MWM) test was performed before a regular treadmill exercise program (5 days/week, 4 weeks). Rats were randomly divided into four groups: group A (no exercise); group B (low intensity, maximal velocity 18 m/min); group C (moderate intensity, maximal velocity 24 m/min) and group D (high intensity, maximal velocity 30 m/min). After 4 weeks, another MWM test was performed, and all rats were sacrificed. RNA sequencing was performed with ipsilesional hippocampal tissue. On the day after cerebral infarction, no differences in escape latency and velocity were observed among the groups. At 4 weeks after cerebral infarction, the escape latencies in groups B, C, and D were shorter than in group A. The escape latencies in groups B and C were shorter than in group D. The velocity in groups A, B, and C was faster than in group D. Thirty gene symbols related to neurogenesis were detected (p < 0.05, fold change > 1.0, average normalized read count > four times). In the neurotrophin-signaling pathway, the CHK gene was upregulated, and the NF-κB gene was downregulated in the low-intensity group. The CHK and NF-κB genes were both downregulated in the moderate-intensity group. The Raf and IRAK genes were downregulated in the high-intensity group. Western blot analysis showed that NF-κB expression was lowest in the moderate-intensity group, whereas CHK and Raf were elevated, and IRAK was decreased in the high-intensity group. Moderate-intensity exercise may contribute to neuroplasticity. Variation in the expression of neurotrophins in neurogenesis according to exercise intensity may reveal the mechanism of neuroplasticity. Thus, NF-κB is the key neurotrophin for neurogenesis related to exercise intensity.

Amicis Omnia Sunt Communia: NF-κB Inhibition as an Alternative to Overcome Osteosarcoma Heterogeneity

Tumor heterogeneity poses a significant challenge in osteosarcoma (OS) treatment. In this regard, the "omics" era has constantly expanded our understanding of biomarkers and altered signaling pathways (i.e., PI3K/AKT/mTOR, WNT/β-catenin, NOTCH, SHH/GLI, among others) involved in OS pathophysiology. Despite different players and complexities, many commonalities have been described, among which the nuclear factor kappa B (NF-κB) stands out. Its altered activation is pervasive in cancer, with pleiotropic action on many disease-relevant traits. Thus, in the scope of this article, we highlight the evidence of NF-κB dysregulation in OS and its integration with other cancer-related pathways while we summarize the repertoire of compounds that have been described to interfere with its action. In silico strategies were used to demonstrate that NF-κB is closely coordinated with other commonly dysregulated signaling pathways not only by functionally interacting with several of their members but also by actively participating in the regulation of their transcription. While existing inhibitors lack selectivity or act indirectly, the therapeutic potential of targeting NF-κB is indisputable, first for its multifunctionality on most cancer hallmarks, and secondly, because, as a common downstream effector of the many dysregulated pathways influencing OS aggressiveness, it turns complex regulatory networks into a simpler picture underneath molecular heterogeneity.

Astrocytic Extracellular Vesicles Regulated by Microglial Inflammatory Responses Improve Stroke Recovery

There are no effective treatments for post-stroke glial scar formation, which inhibits axonal outgrowth and functional recovery after stroke. We investigated whether astrocytic extracellular vesicles (AEVs) regulated by microglia modulate glial scars and improve stroke recovery. We found that peri-infarct glial scars comprised reactive astrocytes with proliferating C3d and decreased S100A10 expression in chronic stroke. In cultured astrocytes, microglia-conditioned media and treatment with P2Y1 receptor antagonists increased and reduced the area of S100A10- and C3d-expressing reactive astrocytes, respectively, by suppressing mitogen-activated protein kinase/nuclear factor-κβ (NF-κB)/tumor necrosis factor-α (TNF-α)/interleukin-1β signaling after oxygen-glucose deprivation. Intracerebral administrations of AEVs enriched miR-146a-5p, downregulated NF-κB, and suppressed TNF-α expressions, by transforming reactive astrocytes to those with S100A10 preponderance, causing functional recovery in rats subjected to middle cerebral artery occlusion. Modulating neuroinflammation in post-stroke glial scars could permit axonal outgrowth, thus providing a basis for stroke recovery with neuroprotective AEVs.

Antidepressant mechanisms of ketamine's action: NF-κB in the spotlight

Ketamine recently approved for therapy of treatment-resistant depression shows a complex and not fully understood mechanism of action. Apart from its classical glutamatergic N-methyl-D-aspartate receptor antagonistic action, it is thought that anti-inflammatory properties of the drug are of clinical relevance due to the contribution of activated inflammatory mediators to the pathophysiology of depression and non-responsiveness of a group of patients to current antidepressant therapies. In a search of the mechanism underlying anti-inflammatory effects of ketamine, the nuclear factor kappa B transcription factor (NF-κB) has been proposed as a target for ketamine. The NF-κB forms precisely regulated protein signaling cascades enabling a rapid response to cellular stimuli. In the central nervous systems, NF-κB signaling appears to have pleiotropic but double-edged functions: on the one hand it participates in the regulation of processes that are crucial in the treatment of depression, such as neuroplasticity, neurogenesis or neuronal survival, on the other - in the activation of neuroinflammation and cell death. Ketamine has been found to reduce inflammation mediated by NF-κB, leading to decreased level of pro-inflammatory cytokines and other inflammatory or stress mediators. Therefore, this review presents recent data on the significance of the NF-κB cascade in the mechanism of ketamine's action and its future perspectives in designing new strategies for the treatment of depression.

Neuron-Specific Enolase (NSE) as a Biomarker for Autistic Spectrum Disease (ASD)

Autistic spectrum disease (ASD) is an increasingly common diagnosis nowadays with a prevalence of 1-2% in most countries. Its complex causality-a combination of genetic, immune, metabolic, and environmental factors-is translated into pleiomorphic developmental disorders of various severity, which have two main aspects in common: repetitive, restrictive behaviors and difficulties in social interaction varying from awkward habits and verbalization to a complete lack of interest for the outside world. The wide variety of ASD causes also makes it very difficult to find a common denominator-a disease biomarker and medication-and currently, there is no commonly used diagnostic and therapeutic strategy besides clinical evaluation and psychotherapy. In the CORDUS clinical study, we have administered autologous cord blood to ASD kids who had little or no improvement after other treatments and searched for a biomarker which could help predict the degree of improvement in each patient. We have found that the neuron-specific enolase (NSE) was elevated above the normal clinical range (less than 16.3 ng/mL) in the vast majority of ASD kids tested in our study (40 of 41, or 97.5%). This finding opens up a new direction for diagnostic confirmation, dynamic evaluation, and therapeutic intervention for ASD kids.

Stress and the brain transcriptome: Identifying commonalities and clusters in standardized data from published experiments

Interpretation of transcriptomic experiments is hindered by many problems including false positives/negatives inherent to big-data methods and changes in gene nomenclature. To find the most consistent effect of stress on brain transcriptome, we retrieved data from 79 studies applying animal models and 3 human studies investigating post-traumatic stress disorder (PTSD). The analyzed data were obtained either with microarrays or RNA sequencing applied to samples collected from more than 1887 laboratory animals and from 121 human subjects. Based on the initial database containing a quarter million differential expression effect sizes representing transcripts in three species, we identified the most frequently reported genes in 223 stress-control comparisons. Additionally, the analysis considers sex, individual vulnerability and contribution of glucocorticoids. We also found an overlap between gene expression in PTSD patients and animals which indicates relevance of laboratory models for human stress response. Our analysis points to genes that, as far as we know, were not specifically tested for their role in stress response (Pllp, Arrdc2, Midn, Mfsd2a, Ccn1, Htra1, Csrnp1, Tenm4, Tnfrsf25, Sema3b, Fmo2, Adamts4, Gjb1, Errfi1, Fgf18, Galnt6, Slc25a42, Ifi30, Slc4a1, Cemip, Klf10, Tom1, Dcdc2c, Fancd2, Luzp2, Trpm1, Abcc12, Osbpl1a, Ptp4a2). Provided transcriptomic resource will be useful for guiding the new research.

Inhibition of RIPK1 by ZJU-37 promotes oligodendrocyte progenitor proliferation and remyelination via NF-κB pathway

Receptor interacting serine/threonine protein kinase 1 (RIPK1) activation and necroptosis have been genetically and mechanistically linked with human multiple sclerosis and neurodegenerative diseases for which demyelination is a common key pathology. Demyelination can be healed through remyelination which is mediated by new oligodendrocytes derived from the adult oligodendrocyte progenitor cells (OPCs). Unfortunately, the efficiency of remyelination declines with progressive aging partially due to the depletion of OPCs following chronic or repeated demyelination. However, to our knowledge, so far there is no drug which enhances proliferation of OPCs, and it is unknown whether inhibiting RIPK1 activity directly affect OPCs, the central player of remyelination. Using TNFα induced RIPK1-dependent necroptosis in Jurkat FADD^−/− cells as a cell death assay, we screened from 2112 FDA-approved drugs and the drug candidates of new RIPK1 inhibitors selected by ourselves, and identified ZJU-37, a small molecule modified by introducing an amide bond to Nec-1s, is a new RIPK1 kinase inhibitor with higher potency than Nec-1s which has the best reported potency. We unveil in addition to protecting myelin from demyelination and axons from degeneration, ZJU-37 exhibits a new role on promoting proliferation of OPCs and enhancing remyelination by inhibiting RIPK1 kinase activity with higher potency than Nec-1s. Mechanistically, ZJU-37 promotes proliferation of OPCs by enhancing the transcription of platelet derived growth factor receptor alpha via NF-κB pathway. This work identifies ZJU-37 as a new drug candidate which enhances remyelination by promoting proliferation of OPCs, paving the way for a potential drug to enhance myelin repair.

The Role of Maternal Immune Activation in the Pathogenesis of Autism: A Review of the Evidence, Proposed Mechanisms and Implications for Treatment

Autism spectrum disorder (ASD) is a neurodevelopmental disease that is characterized by a deficit in social interactions and communication, as well as repetitive and restrictive behaviors. Increasing lines of evidence suggest an important role for immune dysregulation and/or inflammation in the development of ASD. Recently, a relationship between inflammation, oxidative stress, and mitochondrial dysfunction has been reported in the brain tissue of individuals with ASD. Some recent studies have also reported oxidative stress and mitochondrial abnormalities in animal models of maternal immune activation (MIA). This review is focused on the hypothesis that MIA induces microglial activation, oxidative stress, and mitochondrial dysfunction, a deleterious trio in the brain that can lead to neuroinflammation and neurodevelopmental pathologies in offspring. Infection during pregnancy activates the mother’s immune system to release proinflammatory cytokines, such as IL-6, TNF-α, and others. Furthermore, these cytokines can directly cross the placenta and enter the fetal circulation, or activate resident immune cells, resulting in an increased production of proinflammatory cytokines, including IL-6. Proinflammatory cytokines that cross the blood–brain barrier (BBB) may initiate a neuroinflammation cascade, starting with the activation of the microglia. Inflammatory processes induce oxidative stress and mitochondrial dysfunction that, in turn, may exacerbate oxidative stress in a self-perpetuating vicious cycle that can lead to downstream abnormalities in brain development and behavior.

The multifaceted NF-kB: are there still prospects of its inhibition for clinical intervention in pediatric central nervous system tumors?

Despite advances in the understanding of the molecular mechanisms underlying the basic biology and pathogenesis of pediatric central nervous system (CNS) malignancies, patients still have an extremely unfavorable prognosis. Over the years, a plethora of natural and synthetic compounds has emerged for the pharmacologic intervention of the NF-kB pathway, one of the most frequently dysregulated signaling cascades in human cancer with key roles in cell growth, survival, and therapy resistance. Here, we provide a review about the state-of-the-art concerning the dysregulation of this hub transcription factor in the most prevalent pediatric CNS tumors: glioma, medulloblastoma, and ependymoma. Moreover, we compile the available literature on the anti-proliferative effects of varied NF-kB inhibitors acting alone or in combination with other therapies in vitro, in vivo, and clinical trials. As the wealth of basic research data continues to accumulate, recognizing NF-kB as a therapeutic target may provide important insights to treat these diseases, hopefully contributing to increase cure rates and lower side effects related to therapy.

The Neuroinflammatory Role of Pericytes in Epilepsy

Pericytes are a component of the blood-brain barrier (BBB) neurovascular unit, in which they play a crucial role in BBB integrity and are also implicated in neuroinflammation. The association between pericytes, BBB dysfunction, and the pathophysiology of epilepsy has been investigated, and links between epilepsy and pericytes have been identified. Here, we review current knowledge about the role of pericytes in epilepsy. Clinical evidence has shown an accumulation of pericytes with altered morphology in the cerebral vascular territories of patients with intractable epilepsy. In vitro, proinflammatory cytokines, including IL-1β, TNFα, and IL-6, cause morphological changes in human-derived pericytes, where IL-6 leads to cell damage. Experimental studies using epileptic animal models have shown that cerebrovascular pericytes undergo redistribution and remodeling, potentially contributing to BBB permeability. These series of pericyte-related modifications are promoted by proinflammatory cytokines, of which the most pronounced alterations are caused by IL-1β, a cytokine involved in the pathogenesis of epilepsy. Furthermore, the pericyte-glial scarring process in leaky capillaries was detected in the hippocampus during seizure progression. In addition, pericytes respond more sensitively to proinflammatory cytokines than microglia and can also activate microglia. Thus, pericytes may function as sensors of the inflammatory response. Finally, both in vitro and in vivo studies have highlighted the potential of pericytes as a therapeutic target for seizure disorders.

NF-κB disinhibition contributes to dendrite defects in fly models of neurodegenerative diseases

Dendrite pathology is frequently observed in various neurodegenerative diseases (NDs). Although previous studies identified several pathogenic mediators of dendrite defects that act through loss of function in NDs, the underlying pathogenic mechanisms remain largely unexplored. Here, our search for additional pathogenic contributors to dendrite defects in NDs identifies Relish/NF-κB as a novel gain-of-toxicity–based mediator of dendrite defects in animal models for polyglutamine (polyQ) diseases and amyotrophic lateral sclerosis (ALS). In a Drosophila model for polyQ diseases, polyQ-induced dendrite defects require Dredd/Caspase-8–mediated endoproteolytic cleavage of Relish to generate the N-terminal fragment, Rel68, and subsequent Charon-mediated nuclear localization of Rel68. Rel68 alone induced neuronal toxicity causing dendrite and behavioral defects, and we identify two novel transcriptional targets, Tup and Pros, that mediate Rel68-induced neuronal toxicity. Finally, we show that Rel68-induced toxicity also contributes to dendrite and behavioral defects in a Drosophila model for ALS. Collectively, our data propose disinhibition of latent toxicity of Relish/NF-κB as a novel pathogenic mechanism underlying dendrite pathology in NDs.

Fibroblast Growth Factor 9 Stimulates Neuronal Length Through NF-kB Signaling in Striatal Cell Huntington's Disease Models

Proper development of neuronal cells is important for brain functions, and impairment of neuronal development may lead to neuronal disorders, implying that improvement in neuronal development may be a therapeutic direction for these diseases. Huntington's disease (HD) is a neurodegenerative disease characterized by impairment of neuronal structures, ultimately leading to neuronal death and dysfunctions of the central nervous system. Based on previous studies, fibroblast growth factor 9 (FGF9) may provide neuroprotective functions in HD, and FGFs may enhance neuronal development and neurite outgrowth. However, whether FGF9 can provide neuronal protective functions through improvement of neuronal morphology in HD is still unclear. Here, we study the effects of FGF9 on neuronal length in HD and attempt to understand the related working mechanisms. Taking advantage of striatal cell lines from HD knock-in mice, we found that FGF9 increases total neuronal length and upregulates several structural and synaptic proteins under HD conditions. In addition, activation of nuclear factor kappa B (NF-kB) signaling by FGF9 was observed to be significant in HD cells, and blockage of NF-kB leads to suppression of these structural and synaptic proteins induced by FGF9, suggesting the involvement of NF-kB signaling in these effects of FGF9. Taken these results together, FGF9 may enhance total neuronal length through upregulation of NF-kB signaling, and this mechanism could serve as an important mechanism for neuroprotective functions of FGF9 in HD.

Effects of Amyloid Precursor Protein Overexpression on NF-κB, Rho-GTPase and Pro-Apoptosis Bcl-2 Pathways in Neuronal Cells

Background

Alzheimer's disease (AD) is a neurodegenerative disorder that causes cognitive dysfunction. Previous studies have suggested that amyloid plaques, mainly comprising of amyloid-beta peptides, play a pivotal role in AD pathophysiology. This study focuses on the evaluation of the effects of amyloid precursor protein (APP) overexpression on NF-κB, Rho-GTPase and Bcl-2 mediated pro-apoptotic pathways in neuronal cells.

Methods

A lentiviral transduction system was used to generate SH-SY5Y cells overexpressing APP. Immunoblotting was conducted to determine expression levels of NF-κB, Rho-GTPase, and Bcl-2 family proteins in the APP overexpressed cells.

Results

In the NF-κB signaling pathway, APP-overexpressing SH-SY5Y cells showed that there was a reduction of p-NF-κB (p< 0.05) and IKKα. Subsequently, there was upregulation of protein expression of NF-Κb, IKKβ and IκBα. On the other hand, protein expression of RhoC (p< 0.05) and Rac1/2/3 was upregulated as compared to the control group. Meanwhile, a decrease in RhoA, Cdc42 (p< 0.05) and p-Rac1/cdc42 protein levels was observed in the APP-overexpressed group. Lastly, in the pro-apoptotic pathway, the expression of Bcl-2, Bid, Bok and Puma (p< 0.05) was up regulated in the APP-overexpressed group. Downregulation of Bad and Bim expression was observed in the APP-overexpressed as compared to the control group, and Bax expression remained unchanged in the APP-overexpressed group.

Conclusion

APP overexpression regulated signaling in the NF-κB, Rho-GTPase and Bcl-2 family pathways in neuronal cells, suggesting that these are involved in promoting neuronal survival and modulating synaptic plasticity in AD. However, further studies are essential to elucidate the APP-mediated mechanism of action.

Zinc in the Brain: Friend or Foe?

Zinc is a trace metal ion in the central nervous system that plays important biological roles, such as in catalysis, structure, and regulation. It contributes to antioxidant function and the proper functioning of the immune system. In view of these characteristics of zinc, it plays an important role in neurophysiology, which leads to cell growth and cell proliferation. However, after brain disease, excessively released and accumulated zinc ions cause neurotoxic damage to postsynaptic neurons. On the other hand, zinc deficiency induces degeneration and cognitive decline disorders, such as increased neuronal death and decreased learning and memory. Given the importance of balance in this context, zinc is a biological component that plays an important physiological role in the central nervous system, but a pathophysiological role in major neurological disorders. In this review, we focus on the multiple roles of zinc in the brain.

GABA-mediated activated microglia induce neuroinflammation in the hippocampus of mice following cold exposure through the NLRP3 inflammasome and NF-κB signaling pathways

Chronic cold stress has long-term dramatic effects on the animal immune and neuroendocrine systems. As one of the important regions of the brain, the hippocampus is the main region involved in response to stressors. Nevertheless, the impact to the hippocampus following cold exposure and the underlying mechanism involved are not clear. To evaluate the response of the hippocampus during chronic cold stress, male C57BL/6 mice were exposed to 4 °C, 3 h per day for 1 week, after which neuroinflammation and the molecular and signaling pathways in the hippocampus response to cold stress were investigated. To confirm the potential mechanism, BV2 cells were treated with γ-aminobutyric acid (GABA) and BAY 11-7082 and MCC950, then the activation of microglia and key proteins involved in the regulation of inflammation were measured. We demonstrated that chronic cold stress induced the activation of microglia, the emergence of neuroinflammation, and the impairment of neurons in the hippocampus, which might be the result of GABA-mediated activation of nod-like receptor protein 3 (NLRP3) inflammasome and the nuclear factor kappa B (NF-κB) signaling pathway.

Heterogeneity of Neuroinflammatory Responses in Amyotrophic Lateral Sclerosis: A Challenge or an Opportunity?

Amyotrophic Lateral Sclerosis (ALS) is a complex pathology: (i) the neurodegeneration is chronic and progressive; it starts focally in specific central nervous system (CNS) areas and spreads to different districts; (ii) multiple cell types further than motor neurons (i.e., glial/immune system cells) are actively involved in the disease; (iii) both neurosupportive and neurotoxic neuroinflammatory responses were identified. Microglia cells (a key player of neuroinflammation in the CNS) attracted great interest as potential target cell population that could be modulated to counteract disease progression, at least in preclinical ALS models. However, the heterogeneous/multifaceted microglia cell responses occurring in different CNS districts during the disease represent a hurdle for clinical translation of single-drug therapies. To address this issue, over the past ten years, several studies attempted to dissect the complexity of microglia responses in ALS. In this review, we shall summarize these results highlighting how the heterogeneous signature displayed by ALS microglia reflects not only the extent of neuronal demise in different regions of the CNS, but also variable engagement in the attempts to cope with the neuronal damage. We shall discuss novel avenues opened by the advent of single-cell and spatial transcriptomics technologies, underlining the potential for discovery of novel therapeutic targets, as well as more specific diagnostic/prognostic not-invasive markers of neuroinflammation.

Exogenous Hydrogen Sulfide Within the Nucleus Ambiguus Inhibits Gastrointestinal Motility in Rats

Hydrogen sulfide (H₂S) is a neuromodulator in the central nervous system. However, the physiological role of H₂S in the nucleus ambiguus (NA) has rarely been reported. This research aimed to elucidate the role of H₂S in the regulation of gastrointestinal motility in rats. Male Wistar rats were randomly assigned to sodium hydrosulfide (NaHS; 4 and 8 nmol) groups, physiological saline (PS) group, capsazepine (10 pmol) + NaHS (4 nmol) group, L703606 (4 nmol) + NaHS (4 nmol) group, and pyrrolidine dithiocarbamate (PDTC, 4 nmol) + NaHS (4 nmol) group. Gastrointestinal motility curves before and after the injection were recorded using a latex balloon attached with a pressure transducer, which was introduced into the pylorus through gastric fundus. The results demonstrated that NaHS (4 and 8 nmol), an exogenous H₂S donor, remarkably suppressed gastrointestinal motility in the NA of rats (P < 0.01). The suppressive effect of NaHS on gastrointestinal motility could be prevented by capsazepine, a transient receptor potential vanilloid 1 (TRPV1) antagonist, and PDTC, a NF-κB inhibitor. However, the same amount of PS did not induce significant changes in gastrointestinal motility (P > 0.05). Our findings indicate that NaHS within the NA can remarkably suppress gastrointestinal motility in rats, possibly through TRPV1 channels and NF-κB-dependent mechanism.

Emerging role of NIK/IKK2-binding protein (NIBP)/trafficking protein particle complex 9 (TRAPPC9) in nervous system diseases

NFκB signaling and protein trafficking network play important roles in various biological and pathological processes. NIK-and-IKK2-binding protein (NIBP), also known as trafficking protein particle complex 9 (TRAPPC9), is a prototype member of a novel protein family, and has been shown to regulate both NFκB signaling pathway and protein transport/trafficking. NIBP is extensively expressed in the nervous system and plays an important role in regulating neurogenesis and neuronal differentiation. NIBP/TRAPPC9 mutations have been linked to an autosomal recessive intellectual disability syndrome, called NIBP Syndrome, which is characterized by nonsyndromic autosomal recessive intellectual disability along with other symptoms such as obesity, microcephaly, and facial dysmorphia. As more cases of NIBP Syndrome are identified, new light is being shed on the role of NIBP/TRAPPC9 in the central nervous system developments and diseases. NIBP is also involved in the enteric nervous system. This review will highlight the importance of NIBP/TRAPPC9 in central and enteric nervous system diseases, and the established possible mechanisms for developing a potential therapeutic.

Regulation of gene expression after combined scalp acupuncture and transcranial magnetic stimulation in middle cerebral artery occlusion mice

BACKGROUND

The effect of combined repetitive transcranial magnetic stimulation (rTMS) and scalp acupuncture stimulation (SAS) on middle cerebral artery occlusion (MCAO) mice has not yet been reported. The regulation of gene expression after combined stimulation remains unclear.

OBJECTIVE

To analyze gene expression patterns through ribonucleic acid (RNA) sequencing.

METHODS

Thirty-six 8-weeks-old C57BL/6J male mice weighing 50-60 grams were used for this experiment. The MCAO was induced with 60-min occlusion and subsequent reperfusion of the middle cerebral artery. Experimental mice were randomly assigned to four groups, with nine mice in each group, as follows: control group (no treatment), SAS group (10 minutes SAS), rTMS group (1 Hz rTMS), and combined group (1 Hz rTMS and SAS). Stimulation was performed from the 3rd day to the 7th day after the induction of MCAO. All mice were sacrificed, and brain tissues were taken from the motor area of the MCAO lesion. We analyzed their gene expression profiles using RNA sequencing technology.

RESULTS

After stimulation, the grip strength increased in the SAS and rTMS group compared to the control and combined group. The nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) was the key up-regulated protein in the SAS group while src homologus and collagene gene (SHC) and p90 ribosomal protein S6 kinases (p90RSK) were key up-regulated proteins in the rTMS group. However, the C-terminal src kinase-homologous kinase (CHK) was down-regulated whereas p90RSK was up-regulated in the combined group based on the RNA sequencing analysis.

CONCLUSIONS

Each stimulation method showed different patterns with neurotrophin signaling pathway including NFκB, SHC, p90RSK, and CHK. These can be used in further mechanistic studies about gene expression related to neurorecovery.

Pesticides, cognitive functions and dementia: A review

Pesticides are widely-used chemicals commonly applied in agriculture for the protection of crops from pests. Depending on the class of pesticides, the specific substances may have a specific set of adverse effects on humans, especially in cases of acute poisoning. In past years, evidence regarding sequelae of chronic, low-level exposure has been accumulating. Cognitive impairment and dementia heavily affect a person's quality of life and scientific data has been hinting towards an association between them and antecedent chronic pesticide exposure. Here, we reviewed animal and human studies exploring the association between pesticide exposure, cognition and dementia. Additionally, we present potential mechanisms through which pesticides may act neurotoxically and lead to neurodegeneration. Study designs rarely presented homogeneity and the estimation of the exposure to pesticides has been most frequently performed without measuring the synergic effects and the possible interactions between the toxicants within mixtures, and also overlooking low exposures to environmental toxicants. It is possible that a Real-Life Risk Simulation approach would represent a robust alternative for future studies, so that the safe exposure limits and the net risk that pesticides confer to impaired cognitive function can be examined. Previous studies that evaluated the effect of low dose chronic exposure to mixtures of pesticides and other chemicals intending to simulate real life exposure scenarios showed that hormetic neurobehavioral effects can appear after mixture exposure at doses considered safe for individual compounds and these effects can be exacerbated by a coexistence with specific conditions such as vitamin deficiency. However, there is an overall indication, derived from both epidemiologic and laboratory evidence, supporting an association between exposure to neurotoxic pesticides and cognitive dysfunction, dementia and Alzheimer's disease.

The ubiquitin-editing enzyme A20 regulates synapse remodeling and efficacy

Ubiquitination and its reverse process, deubiquitination, play essential roles in neural development, function, and plasticity. A20, a ubiquitin editing enzyme that can remove K63-polyubiquitin chains from substrates and attach K48-polyubiquitin chains to them, is a critical component in the NF-κB signaling pathway in the immune system. This dual ubiquitin enzyme is also present in mammalian brains, but its potential role in neurons and synapses is unknown. We show that A20 in pyramidal neurons potently regulates dendritic arborization, spine morphogenesis, and synaptic transmission through an NF-κB-dependent mechanism. In cultured hippocampal neurons, overexpression of A20 reduced dendritic complexity and spine size and density, whereas A20 knockdown increased spine size and density, as well as clustering of the postsynaptic scaffold PSD-95 and glutamate receptor subunit GluA1. A20 effects in vitro were recapitulated in vivo where increasing or decreasing A20 expression in mouse brains reduced and enhanced spine density, respectively. Functionally, A20 knockdown significantly increased the amplitude, but not frequency of miniature excitatory postsynaptic currents, suggesting a role in postsynaptic efficacy. A20 negatively regulated NF-κB activation in neurons and A20 mutants deficient in either the deubiquitinase or the ubiquitin ligase activity failed to suppress NF-κB activation or reduce spine morphogenesis. Finally, selective inhibition of NF-κB abolished A20 knockdown-elicited spine formation, suggesting that A20 exerts its modulation on synapses through NF-κB signaling. Together, our study reveals a previously unknown role for A20, the only known ubiquitin editing enzyme with both deubiquitinase and ubiquitin ligase activity, in dendritic arborization, spine remodeling, and synaptic plasticity.

Recovery of inferior alveolar nerve by photobiomodulation therapy using two laser wavelengths: A behavioral and immunological study in rat

Postoperative sensory disturbances of inferior alveolar nerve (IAN) are major challenges in dental procedures. We aimed to investigate the effect of photobiomodulation therapy (PBMT) with 810 nm and 980 nm diode lasers on behavioral and immunological factors in a rat IAN crush model. Seventy-two rats were randomly assigned to the four groups of 810 nm laser (crush injury+810 nm laser; 6 J/cm², 15 sessions, every 48 h), 980 nm laser (crush injury+980 nm laser; same protocol), control (crush injury without irradiation), and sham surgery (no crush injury and no irradiation). The neurosensory response of IAN was evaluated by Von Frey behavioral test before (baseline) and post-surgery in a period of one month. Changes of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), nuclear factor-kappa B (NF-κB), TNF-α, and IL-1β, were assessed on days 2 and 30 post injury. Data were analyzed for significant differences by repeated measures and one-way ANOVA (p < .05). One day after surgery, all rats subjected to nerve injury showed significant increase in the withdrawal threshold of von Frey test compared to the baseline (p = .02 for control and p = .03 for laser groups). The threshold gradually returned to the baseline scores in 810 nm, 980 nm, and control groups from days 11, 17, and 29, respectively. There was a significant lower withdrawal threshold in 810 nm and 980 nm laser groups compared to the control group in days 11 to 19 and 9 to 23, respectively. At both time points, the levels of NGF and BDNF were significantly higher in 810 nm laser group compared to the control group. There was a significant difference between laser and control groups regarding NF-κB expression (all p values<.001). TNF-α and IL-1β were significantly lower in laser groups compared to the control group (all p values < .001). PBMT with 810 and 980 nm diode laser protocol used in this study, promoted the neurosensory recovery of IAN after crush injury in rats. In addition, application of 810 nm diode laser was associated with more improvement in immunological responses compared to that of 980 nm laser.

Role of Nuclear Factor Kappa B (NF-κB) Signalling in Neurodegenerative Diseases: An Mechanistic Approach

A transcriptional regulatory nuclear factor kappa B (NF-κB) protein is a modulator of cellular biological activity via binding to a promoter region in the nucleus and transcribing various protein genes. The recent research implicated the intensive role of nuclear factor kappa B (NF-κB) in diseases like autoimmune disorder, inflammatory, cardiovascular and neurodegenerative diseases. Therefore, targeting the nuclear factor kappa B (NF-κB) protein offers a new opportunity as a therapeutic approach. Activation of IκB kinase/NF-κB signaling pathway leads to the development of various pathological conditions in human beings, such as neurodegenerative, inflammatory disorders, autoimmune diseases, and cancer. Therefore, the transcriptional activity of IκB kinase/NF- κB is strongly regulated at various cascade pathways. The nuclear factor NF-kB pathway plays a major role in the expression of pro-inflammatory genes, including cytokines, chemokines, and adhesion molecules. In response to the diverse stimuli, the cytosolic sequestered NF-κB in an inactivated form by binding with an inhibitor molecule protein (IkB) gets phosphorylated and translocated into the nucleus further transcribing various genes necessary for modifying various cellular functions. The various researches confirmed the role of different family member proteins of NF-κB implicated in expressing various genes products and mediating various cellular cascades. MicroRNAs, as regulators of NF- κB microRNAs play important roles in the regulation of the inflammatory process. Therefore, the inhibitor of NF-κB and its family members plays a novel therapeutic target in preventing various diseases. Regulation of NF- κB signaling pathway may be a safe and effective treatment strategy for various disorders.

Associations between autistic-like traits and polymorphisms in NFKBIL1

OBJECTIVE

The immune system has been suggested to be associated with neuropsychiatric disorders; for example, elevated levels of cytokines and the inflammation-related transcription factor nuclear factor kappa-B (NF-κB) have been reported in individuals with autism spectrum disorder (ASD). The aim of this study was to investigate possible associations between autistic-like traits (ALTs) and single nucleotide polymorphisms (SNPs) in NFKB1 (encoding a subunit of the NF-κB protein complex) and NF-κB inhibitor-like protein 1 (NFKBIL1).

METHODS

The study was conducted in a cohort from the general population: The Child and Adolescent Twin Study in Sweden (CATSS, n = 12 319, 9-12 years old). The subjects were assessed by the Autism-Tics, ADHD, and Other Comorbidities Inventory. Five SNPs within the two genes were genotyped (NFKBIL1: rs2857605, rs2239707, rs2230365 and rs2071592; NFKB1: rs4648022).

RESULTS

We found significant associations for two SNPs in NFKBIL1: rs2239707 showed a significant distribution of genotype frequencies in the case-control analysis both for all individuals combined and in boys only, and rs2230365 was significantly associated with the ALTs-module language impairment in boys only. Furthermore, we found nominal association in the case-control study for rs2230365, replicating earlier association between this SNP and ASD in an independent genome-wide association study.

CONCLUSION

The shown associations between polymorphisms in NFKBIL1 and ALTs are supporting an influence of the immune system on neuropsychiatric symptoms.

Regulating glycolysis, the TLR4 signal pathway and expression of RBM3 in mouse liver in response to acute cold exposure

At low temperatures, the liver increases glucose utilization and expresses RNA-binding motif 3 (RBM3) to cope with cold exposure. In this study, the expression of heat shock protein 70 (HSP70), Toll-like receptor 4 (TLR4), bone marrow differentiation factor 88 (MYD88), and phosphorylated nuclear factor-κB (NF-κB) was consistent with fluctuations in insulin in fasted cold-exposed mice. We also found up-regulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in acute cold exposure with a decrease in core body temperature. RBM3 transcription and translation were activated 2 h after cold exposure. The anti-apoptotic factor Bcl-2/Bax ratio also increased, while expression of apoptosis factors: cleaved caspase-3, cleaved poly(ADP-ribose)polymerase 1 (PARP-1) and cytochrome-c (Cyt-c) was unchanged. Liver glycogen was depleted after 2 h of cold exposure, and blood glucose decreased after 4 h. Glycogen synthase kinase 3β (GSK3β) phosphorylation continued to increase to promote hepatic glycogen synthesis. We found a high level of protein kinase B (AKT) phosphorylation after 6 h of cold exposure. In addition, we demonstrated that after cold exposure for 2 h, in the liver, continued phosphorylation of fructose-2,6-diphosphate (PFKFB2) and decreased accumulation of glycogen intermediates fructose-1,6-diphosphate (FDP) and pyruvic acid (PA). In summary, the liver responds to cold exposure through a number of different pathways, including activation of HSP70/TLR4 signaling pathways, up-regulation of RBM3 expression, and increased glycolysis and glycogen synthesis. We propose a possible signaling pathway in which regulation of RBM3 expression by the liver affects the AKT metabolic signaling pathway. Lay summary In response to changes in ambient temperature, mice regulate global metabolism and gene expression through hormones. This study focused on the effects of environmental hypothermia on molecular pathways of glucose metabolism in the liver, which is the important metabolic organ in mice. This provides a basis for further study of mice against cold exposure damage.

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.

Mechanisms underpinning AMP-activated protein kinase-related effects on behavior and hippocampal neurogenesis in an animal model of depression

Adenosine monophosphate-activated protein kinase (AMPK) is critical for whole-body energy metabolism regulation. Recent studies have suggested that physical exercise ameliorates depressive-like behaviors via AMPK activation; however, the underlying mechanism is unclear. Here, we examined the effects and underlying mechanisms of AMPK activation on depressive-like behavior in olfactory bulbectomized (OBX) mice. We treated OBX mice with the AMPK activator, 5-aminoimidazole-4-carboxamide-1-β-d-ribonucleotide (AICAR) on the 7th or 14th day after bilateral bulbectomy and evaluated depressive-like behavior using the tail-suspension test (TST) and forced swimming test (FST) on the 21st day. The expression of phosphorylated AMPK, protein kinase C ζ (PKCζ), nuclear factor-kappa B (NF-κB), brain-derived neurotrophic factor (BDNF), and cAMP response element-binding protein (CREB) in the hippocampus was assessed by western blotting. Hippocampal neurogenesis and localization of AMPK and phosphorylated NF-κB were examined by immunohistochemistry. Chronic AICAR treatment suppressed the prolonged immobility of OBX mice in the TST and FST, and increased the levels of phosphorylated AMPK, PKCζ, NF-κB, CREB, and BDNF. Hippocampal neurogenesis in OBX mice was promoted by chronic AICAR treatment. Co-administration of AICAR with the PKCζ inhibitor or the neurotrophic tyrosine kinase receptor type 2 (TrkB) antagonist, ANA-12, inhibited these effects. Phosphorylated AMPK was detected in mature and immature hippocampal neurons and microglia, while phosphorylated NF-κB was detected only in neurons in AICAR-treated OBX mice. These data indicate that AMPK activation produces anti-depressant effects, which are mediated by elevated hippocampal neurogenesis potentially via PKCζ/NF-κB/BDNF/TrkB/CREB signaling in neurons.

Cell Type-Specific Roles of NF-κB Linking Inflammation and Thrombosis

The transcription factor NF-κB is a central mediator of inflammation with multiple links to thrombotic processes. In this review, we focus on the role of NF-κB signaling in cell types within the vasculature and the circulation that are involved in thrombo-inflammatory processes. All these cells express NF-κB, which mediates important functions in cellular interactions, cell survival and differentiation, as well as expression of cytokines, chemokines, and coagulation factors. Even platelets, as anucleated cells, contain NF-κB family members and their corresponding signaling molecules, which are involved in platelet activation, as well as secondary feedback circuits. The response of endothelial cells to inflammation and NF-κB activation is characterized by the induction of adhesion molecules promoting binding and transmigration of leukocytes, while simultaneously increasing their thrombogenic potential. Paracrine signaling from endothelial cells activates NF-κB in vascular smooth muscle cells and causes a phenotypic switch to a “synthetic” state associated with a decrease in contractile proteins. Monocytes react to inflammatory situations with enforced expression of tissue factor and after differentiation to macrophages with altered polarization. Neutrophils respond with an extension of their life span—and upon full activation they can expel their DNA thereby forming so-called neutrophil extracellular traps (NETs), which exert antibacterial functions, but also induce a strong coagulatory response. This may cause formation of microthrombi that are important for the immobilization of pathogens, a process designated as immunothrombosis. However, deregulation of the complex cellular links between inflammation and thrombosis by unrestrained NET formation or the loss of the endothelial layer due to mechanical rupture or erosion can result in rapid activation and aggregation of platelets and the manifestation of thrombo-inflammatory diseases. Sepsis is an important example of such a disorder caused by a dysregulated host response to infection finally leading to severe coagulopathies. NF-κB is critically involved in these pathophysiological processes as it induces both inflammatory and thrombotic responses.

Influence of pharmacological and epigenetic factors to suppress neurotrophic factors and enhance neural plasticity in stress and mood disorders

Stress-induced major depression and mood disorders are characterized by behavioural abnormalities and psychiatric illness, leading to disability and immature mortality worldwide. Neurobiological mechanisms of stress and mood disorders are discussed considering recent findings, and challenges to enhance pharmacological effects of antidepressant, and mood stabilizers. Pharmacological enhancement of ketamine and scopolamine regulates depression at the molecular level, increasing synaptic plasticity in prefrontal regions. Blood-derived neurotrophic factors facilitate mood-deficit symptoms. Epigenetic factors maintain stress-resilience in hippocampal region. Regulation of neurotrophic factors blockades stress, and enhances neuronal survival though it paralyzes limbic regions. Molecular agents and neurotrophic factors also control behavioral and synaptic plasticity in addiction and stress disorders. Future research on neuronal dynamics and cellular actions can be directed to obtain the etiology of synaptic dysregulation in mood disorder and stress. For the first time, the current review contributes to the literature of synaptic plasticity representing the role of epigenetic mechanisms and glucocorticoid receptors to predict depression and anxiety in clinical conditions.

Coiled-coil structure-dependent interactions between polyQ proteins and Foxo lead to dendrite pathology and behavioral defects

It remains unclear how the structural properties of polyglutamine (polyQ) proteins, which underlie several neurodegenerative disorders, including Huntington’s disease and spinocerebellar ataxias (SCAs), translate into the toxicity of these proteins. Here, we demonstrate that coiled-coil structures in expanded polyQ regions of SCA type 3 (SCA3) proteins cause dendrite defects in Drosophila neurons, as well as behavioral abnormalities. Moreover, interactions of SCA3 with Foxo mediated by coiled-coil domains of these two proteins resulted in functional impairment of this transcription factor, whereas its overexpression significantly rescued the SCA3-induced defects. Our study expanded the current understanding of neuronal pathology mediated by polyQ proteins via the coiled-coil–mediated interactions. These results may have important implications in therapeutic strategies for polyQ protein-related diseases.

Neurodegenerative disorders, such as Huntington’s diseases and spinocerebellar ataxias (SCAs), are driven by proteins with expanded polyglutamine (polyQ) tracts. Recently, coiled-coil structures in polyQ regions of such proteins were shown to facilitate aggregate formation and ultimately lead to cell death. However, the molecular mechanism linking these structural domains to neuronal toxicity of polyQ proteins remains elusive. Here, we demonstrate that coiled-coil structures in the Q repeat region of SCA type 3 (SCA3) polyQ proteins confer protein toxicity in Drosophila neurons. To functionally characterize coiled-coil structures in the Q repeat regions, we generated three structural variants of SCA3 polyQ proteins: (i) MJDtr-76Q, containing both α-helical coiled-coil and β-sheet hairpin structures in the Q repeat region; (ii) MJDtr-70Q_cc0, possessing only α-helical coiled-coil structures due to the incorporation of β-sheet–breaking residues (Q-to-N or Q-to-E mutations); and (iii) MJDtr-70Q_pQp, with no secondary structure due to the introduced proline residues (Q-to-P mutations). Through comparative analysis of these variants, we found that coiled-coil structures facilitated nuclear localization of SCA3 polyQ proteins and induced dendrite defects in Drosophila dendritic arborization neurons. Furthermore, genetic and functional screening identified the transcription factor Foxo as a target of polyQ proteins, and coiled-coil–mediated interactions of Foxo and polyQ proteins in the nucleus resulted in the observed dendrite and behavioral defects in Drosophila. These results demonstrate that coiled-coil structures of polyQ proteins are crucial for their neuronal toxicity, which is conferred through coiled-coil to coiled-coil interactions with the nuclear targets of these proteins.

Upregulation of CX3CL1 mediated by NF-κB activation in dorsal root ganglion contributes to peripheral sensitization and chronic pain induced by oxaliplatin administration

Painful peripheral neuropathy is a severe side effect in oxaliplatin therapy that compromises cancer patients' quality of life. However, its underlying pathogenic mechanisms remain largely unknown. Here, we found that intraperitoneal consecutive administration of oxaliplatin significantly increased excitability of small diameter dorsal root ganglion neurons and induced thermal hyperalgesia in rats. Furthermore, the CX3CL1 expression was significantly increased after oxaliplatin treatment, and intrathecal injection of a neutralizing antibody against CX3CL1 markedly attenuated the enhanced excitability of dorsal root ganglion neurons and thermal hyperalgesia. Importantly, the upregulated CX3CL1 is mediated by the NF-κB signaling pathway, as inhibition of NF-κB p65 activation with pyrrolidine dithiocarbamate or p65 siRNA inhibited the upregulation of CX3CL1, the enhanced excitability of dorsal root ganglion neurons, and thermal hyperalgesia induced by oxaliplatin. Further studies with chromatin immunoprecipitation found that oxaliplatin treatment increased the recruitment of NF-κB p65 to the CX3Cl1 promoter region. Our results suggest that upregulation of CX3CL1 in dorsal root ganglion mediated by NF-κB activation contributes to the peripheral sensitization and chronic pain induced by oxaliplatin administration.

Circadian clock component PERIOD2 regulates diurnal expression of Na+/H+ exchanger regulatory factor-1 and its scaffolding function

A number of diverse cell-surface proteins are anchored to the cytoskeleton via scaffold proteins. Na⁺/H⁺ exchanger regulatory factor-1 (NHERF1), encoded by the Slc9a3r1 gene, functions as a scaffold protein, which is implicated in the regulation of membrane expression of various cell-surface proteins. Here, we demonstrate that the circadian clock component PERIOD2 (PER2) modulates transcription of the mouse Slc9a3r1 gene, generating diurnal accumulation of NHERF1 in the mouse liver. Basal expression of Slc9a3r1 was dependent on transcriptional activation by p65/p50. PER2 bound to p65 protein and prevented p65/p50-mediated transactivation of Slc9a3r1. The time-dependent interaction between PER2 and p65 underlay diurnal oscillation in the hepatic expression of Slc9a3r1/NHERF1. The results of immunoprecipitation experiments and liquid chromatography-mass spectrometry analysis of mouse liver revealed that NHERF1 time-dependently interacted with fatty acid transport protein-5 (FATP5). Temporary accumulation of NHERF1 protein stabilized plasmalemmal localization of FATP5, thereby enhancing hepatic uptake of fatty acids at certain times of the day. Our results suggest an unacknowledged role for PER2 in regulating the diurnal expression of NHERF1 in mouse liver. This machinery also contributed to diurnal changes in the ability of hepatic cells to uptake fatty acids.

JSH-23 prevents depressive-like behaviors in mice subjected to chronic mild stress: Effects on inflammation and antioxidant defense in the hippocampus

Nuclear factor-kappa B (NF-κB), which is reported to play an important role in the pathogenesis of depression, also has a central role in the genesis and progression of inflammation. Here, we have targeted the nuclear translocation of NF-κB using 4-methyl-N1-(3-phenyl-propyl)-benzene-1,2-diamine (JSH-23) to elucidate its role in depression. We investigated the antidepressant-like effects of JSH-23 in the chronic mild stress (CMS) mouse model, which is a valid, reasonably reliable, and useful model of depression. The antidepressant-like effects of JSH-23 were evaluated using the sucrose preference test (SPT) and the forced swimming test (FST). We also assessed inflammatory markers [interleukin (IL)-6 and tumor necrosis factor-α (TNF-α)] and components of antioxidant defense [superoxide dismutase (SOD) and nuclear factor erythroid-2-related factor 2 (Nrf 2)] in the hippocampus. Fluoxetine, a classical antidepressant, was used in this study as a positive control. Administration of JSH-23 significantly prevented the decreased sucrose preference in the SPT and prevented the increased immobility time in the FST caused by CMS, but had no effect on locomotor activity. Expression of NF-κB p65 protein in the hippocampus was decreased, and elevated levels of IL-6 and TNF-α were reduced, after JSH-23 administration. In addition to its anti-inflammatory effect, JSH-23 treatment increased the expression of SOD and Nrf 2 in the hippocampus, suggesting that it strengthens antioxidant defense. The current study demonstrated that inhibiting the NF-κB signaling cascade using JSH-23 prevented depressive-like behaviors by decreasing inflammation and improving antioxidant defense in the hippocampus. We concluded that NF-κB activation plays an important role in the pathophysiology of depression and that targeting NF-κB signaling may provide a novel and effective therapy for depression. Additional preclinical studies and clinical trials are, however, needed to further elucidate the effects of this therapeutic strategy.

High-throughput screen for compounds that modulate neurite growth of human induced pluripotent stem cell-derived neurons

Development of technology platforms to perform compound screens of human induced pluripotent stem cell (hiPSC)-derived neurons with relatively high throughput is essential to realize their potential for drug discovery. Here, we demonstrate the feasibility of high-throughput screening of hiPSC-derived neurons using a high-content, image-based approach focused on neurite growth, a process that is fundamental to formation of neural networks and nerve regeneration. From a collection of 4421 bioactive small molecules, we identified 108 hit compounds, including 37 approved drugs, that target molecules or pathways known to regulate neurite growth, as well as those not previously associated with this process. These data provide evidence that many pathways and targets known to play roles in neurite growth have similar activities in hiPSC-derived neurons that can be identified in an unbiased phenotypic screen. The data also suggest that hiPSC-derived neurons provide a useful system to study the mechanisms of action and off-target activities of the approved drugs identified as hits, leading to a better understanding of their clinical efficacy and toxicity, especially in the context of specific human genetic backgrounds. Finally, the hit set we report constitutes a sublibrary of approved drugs and tool compounds that modulate neurites. This sublibrary will be invaluable for phenotypic analyses and interrogation of hiPSC-based disease models as probes for defining phenotypic differences and cellular vulnerabilities in patient versus control cells, as well as for investigations of the molecular mechanisms underlying human neurite growth in development and maintenance of neuronal networks, and nerve regeneration.

Summary: High-throughput, small molecule screening of hiPSC-derived neurons using a high-content, image-based approach focused on neurite growth identified hit compounds, including approved drugs, which target molecules or pathways known to regulate neurite growth.

Maternal IL-17A in autism

Although autism spectrum disorder (ASD) has a strong genetic basis, its etiology is complex, with several genetic factors likely to be involved as well as environmental factors. Immune dysregulation has gained significant attention as a causal mechanism in ASD pathogenesis. ASD has been associated with immune abnormalities in the brain and periphery, including inflammatory disorders and autoimmunity in not only the affected individuals but also their mothers. Prenatal exposure to maternal immune activation (MIA) has been implicated as an environmental risk factor for ASD. In support of this notion, animal models have shown that MIA results in offspring with behavioral, neurological, and immunological abnormalities similar to those observed in ASD. This raises the question of how MIA exposure can lead to ASD in susceptible individuals. Recent evidence points to a potential inflammation pathway linking MIA-associated ASD with the activity of T helper 17 (Th17) lymphocytes and their effector cytokine interleukin-17A (IL-17A). IL-17A has been implicated from human studies and elevated IL-17A levels in the blood have been found to correlate with phenotypic severity in a subset of ASD individuals. In MIA model mice, elevated IL-17A levels also have been observed. Additionally, antibody blockade to inhibit IL-17A signaling was found to prevent ASD-like behaviors in offspring exposed to MIA. Therefore, IL-17A dysregulation may play a causal role in the development of ASD. The source of increased IL-17A in the MIA mouse model was attributed to maternal Th17 cells because genetic removal of the transcription factor RORγt to selectively inhibit Th17 differentiation in pregnant mice was able to prevent ASD-like behaviors in the offspring. Similar to ASD individuals, the MIA-exposed offspring also displayed cortical dysplasia which could be prevented by inhibition of IL-17A signaling in pregnant mice. This finding reveals one possible cellular mechanism through which ASD-related cognitive and behavioral deficits may emerge following maternal inflammation. IL-17A can exert strong effects on cell survival and differentiation and the activity of signal transduction cascades, which can have important consequences during cortical development on neural function. This review examines IL-17A signaling pathways in the context of both immunity and neural function that may contribute to the development of ASD associated with MIA.

Reduction of NF-κB (p65) in Scrapie-Infected Cultured Cells and in the Brains of Scrapie-Infected Rodents

Transcription factor NF-κB functions as a pleiotropic regulator of target genes controlling physiological function as well as pathological processes of many different diseases, including some neurodegenerative diseases. However, the role of NF-κB in the pathogenesis of prion disease remains ambiguous. In this study, the status of NF-κB (p65) in a prion-infected cell line SMB-S15 was first evaluated. Significantly lower levels of p65 and the phosphorylated form of p65 (p-p65) were detected in SMB-S15 cells, compared with its normal partner cell line SMB-PS. Markedly slower responses of the NF-κB system to the stimulation of TNF-α were observed in SMB-S15 cells. Removal of PrP^Sc replication in SMB-S15 cells rescued the expression and activity of NF-κB. However, overexpression of p65 in SMB-S15 cells did not influence the propagation of PrP^Sc. Moreover, significant decline of p65 level was also observed in the brain tissues of mice infected with the lysates of SMB-S15 cells and hamsters infected with scrapie agent 263K at terminal stage. Immunofluorescence assays (IFAs) on brain sections from either normal or scrapie-infected rodents revealed colocalization of p65 with neuronal nuclear (NeuN) protein positive cells but not with glial fibrillary acidic protein (GFAP) positive cells. Assays of the agents involving in the regulation of NF-κB showed down-regulated phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB/Akt) both in SMB-S15 cells and in the brains of scrapie-infected rodents. Those data indicate a remarkable repression of the classical NF-κB pathway during prion infection both in vitro and in vivo. The alteration of NF-κB (p65) shows close association with the replication and accumulation of PrP^Sc in the cells.

The Role of NFkB in Drug Addiction: Beyond Inflammation

Aims

Nuclear factor kappa light chain enhancer of activated B cells (NFkB) is a ubiquitous transcription factor well known for its role in the innate immune response. As such, NFkB is a transcriptional activator of inflammatory mediators such as cytokines. It has recently been demonstrated that alcohol and other drugs of abuse can induce NFkB activity and cytokine expression in the brain. A number of reviews have been published highlighting this effect of alcohol, and have linked increased NFkB function to neuroimmune-stimulated toxicity. However, in this review we focus on the potentially non-immune functions of NFkB as possible links between NFkB and addiction.

Methods

An extensive review of the literature via Pubmed searches was used to assess the current state of the field.

Results

NFkB can induce the expression of a diverse set of gene targets besides inflammatory mediators, some of which are involved in addictive processes, such as opioid receptors and neuropeptides. NFkB mediates complex behaviors including learning and memory, stress responses, anhedonia and drug reward, processes that may lie outside the role of NFkB in the classic neuroimmune response.

Conclusions

Future studies should focus on these non-immune functions of NFkB signaling and their association with addiction-related processes.

Toll-Like Receptor 2 Is a Regulator of Circadian Active and Inactive State Consolidation in C57BL/6 Mice

Regulatory systems required to maintain behavioral arousal remain incompletely understood. We describe a previously unappreciated role that toll-like receptor 2 (Tlr2, a membrane bound pattern recognition receptor that recognizes specific bacterial, viral, and fungal peptides), contributes toward regulation of behavioral arousal. In 4–4.5 month old mice with constitutive loss of Tlr2 function (Tlr2^−/− mice), we note a marked consolidation in the circadian pattern of both active and inactive states. Specifically, Tlr2^−/− mice demonstrated significantly fewer but longer duration active states during the circadian dark cycle, and significantly fewer but longer duration inactive states during the circadian light cycle. Tlr2^−/− mice also consumed less food and water, and moved less during the circadian light cycle. Analysis of circadian rhythms further suggested that Tlr2^−/− mice demonstrated less day-to-day variability in feeding, drinking, and movement behaviors. Reevaluation of this same mouse cohort at age 8–8.5 months revealed a clear blunting of these differences. However, Tlr2^−/− mice were still noted to have fewer short-duration active states during the circadian dark cycle, and continued to demonstrate significantly less day-to-day variability in feeding, drinking, and movement behaviors. These results suggest that Tlr2 function may have a role in promoting transitions between active and inactive states. Prior studies have demonstrated that Tlr2 regulates sickness behaviors including hypophagia, hyperthermia, and decreased activity. Our work suggests that Tlr2 function also evokes behavioral fragmentation, another aspect of sickness behavior and a clinically significant problem of older adults.

The Influence of Fluorine on the Disturbances of Homeostasis in the Central Nervous System

Fluorides occur naturally in the environment, the daily exposure of human organism to fluorine mainly depends on the intake of this element with drinking water and it is connected with the geographical region. In some countries, we can observe the endemic fluorosis-the damage of hard and soft tissues caused by the excessive intake of fluorine. Recent studies showed that fluorine is toxic to the central nervous system (CNS). There are several known mechanisms which lead to structural brain damage caused by the excessive intake of fluorine. This element is able to cross the blood-brain barrier, and it accumulates in neurons affecting cytological changes, cell activity and ion transport (e.g. chlorine transport). Additionally, fluorine changes the concentration of non-enzymatic advanced glycation end products (AGEs), the metabolism of neurotransmitters (influencing mainly glutamatergic neurotransmission) and the energy metabolism of neurons by the impaired glucose transporter-GLUT1. It can also change activity and lead to dysfunction of important proteins which are part of the respiratory chain. Fluorine also affects oxidative stress, glial activation and inflammation in the CNS which leads to neurodegeneration. All of those changes lead to abnormal cell differentiation and the activation of apoptosis through the changes in the expression of neural cell adhesion molecules (NCAM), glial fibrillary acidic protein (GFAP), brain-derived neurotrophic factor (BDNF) and MAP kinases. Excessive exposure to this element can cause harmful effects such as permanent damage of all brain structures, impaired learning ability, memory dysfunction and behavioural problems. This paper provides an overview of the fluoride neurotoxicity in juveniles and adults.

Maternal marginal iodine deficiency limits dendritic growth of cerebellar purkinje cells in rat offspring by NF-κB signaling and MAP1B

Iodine deficiency (ID) during early pregnancy had an adverse effect on children's psychomotor and motor function. It is worth noting that maternal marginal ID tends to be a common public health problem. Whether marginal ID potentially had adverse effects on the development of cerebellum and the underlying mechanisms remain unclear. Therefore, our aim was to study the effects of marginal ID on the dendritic growth in filial cerebellar Purkinje cells (PCs) and the underlying mechanism. In the present study, we established Wistar rat models by feeding dam rats with a diet deficient in iodine and deionized water supplemented with potassium iodide. We examined the total dendritic length using immunofluorescence, and Western blot analysis was conducted to investigate the activity of nuclear factor-κB (NF-κB) signaling and microtubule-associated protein 1B (MAP1B). Our results showed that marginal ID reduced the total dendritic length of cerebellar PCs, slightly down-regulated the activity of NF-κB signaling and decreased MAP1B in cerebellar PCs on postnatal day (PN) 7, PN14, and PN21. Our study may support the hypothesis that decreased T₄ induced by marginal ID limits PCs dendritic growth, which may involve in the disturbance of NF-κB signaling and MAP1B on the cerebellum. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1241-1251, 2017.

Time-lapse imaging of p65 and IκBα translocation kinetics following Ca2+-induced neuronal injury reveals biphasic translocation kinetics in surviving neurons

The transcription factor nuclear factor-κB (NF-κB) regulates neuronal differentiation, plasticity and survival. It is well established that excitatory neurotransmitters such as glutamate control NF-κB activity. Glutamate receptor overactivation is also involved in ischemic- and seizure-induced neuronal injury and neurodegeneration. However, little is known at the single cell-level how NF-κB signaling relates to neuronal survival during excitotoxic injury. We found that silencing of p65/NF-κB delayed N-methyl-d-aspartate (NMDA)-induced excitotoxic injury in hippocampal neurons, suggesting a functional role of p65 in excitotoxicity. Time-lapse imaging of p65 and its inhibitor IκBα using GFP and Cerulean fusion proteins revealed specific patterns of excitotoxic NF-κB activation. Nuclear translocation of p65 began on average 8±3min following 15min of NMDA treatment and was observed in up to two thirds of hippocampal neurons. Nuclear translocation of IκBα preceded that of p65 suggesting independent translocation processes. In surviving neurons, the onset of p65 nuclear export correlated with mitochondrial membrane potential recovery. Dying neurons exhibited persistent nuclear accumulation of p65-eGFP until plasma membrane permeabilization. Our data demonstrate an important role for p65 activation kinetics in neuronal cell death decisions following excitotoxic injury.