Targeting of Tumor Necrosis Factor Alpha Receptors as a Therapeutic Strategy for Neurodegenerative Disorders

TNF receptors: Structure-function relationships and therapeutic targeting strategies

Tumor necrosis factor receptors (TNFR1 and TNFR2) play key roles in mediating inflammatory response and cell death signaling, which are associated with autoimmune disorders, neurodegenerative diseases, and cancers. The structure-function relationships of TNF receptors and their ligands determine the activation or inhibition of downstream signaling pathways. Available crystal structures have provided critical insights into the therapeutic targeting strategies of TNF receptors and their signaling networks. In this review, we discuss the potential of targeting receptor-ligand and receptor-receptor interactions in a competitive manner as well as perturbing receptor conformational dynamics through an allosteric mechanism to modulate TNF receptor signaling. We propose that conformational states of TNF receptors can act as a molecular switch in determining their functions and are important therapeutic targets. The knowledge of the structure-function relationships of TNF receptors can be applied to translational high-throughput drug screening and design of novel receptor-specific modulators with enhanced pharmacological properties.

Towards understanding the role of nanomedicine in targeting TNFR2 in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammation of the synovium and progressive joint destruction which significantly affects both quality of life and socioeconomic status. Admittedly, various treatments are available, but they are usually accompanied by various side effects, from mild to severe, and potentially with adverse events. Tumour necrosis factor-alpha (TNF-α) plays a crucial role in the pathophysiology of RA. It promotes inflammatory, apoptosis and necroptosis via TNF receptor-1 (TNFR1) but elicit anti-inflammatory effects via TNFR2. Herein, targeting TNFR2 has gained attention in RA studies. Understanding the role of nanomedicine in modulating TNFR2 signalling may be the instrument in development of RA therapies. Nanotechnology has made a significant progress in treating various conditions of diseases since its inception. Due to this, nanomedicine has emerged as a promising therapeutics approach for RA. Recent studies have demonstrated the potential of nanomedicine in RA theranostics, combining therapy and diagnostics for improved treatment outcomes. Owing to the challenges and advancements in the field of nanotechnology, nanoparticles are seen as an applicable candidate in the treatment of RA. In this review, we provide an overview of the role of nanomedicine in targeting TNFR2 for the treatment of RA and highlight the limitations of current therapies as well as the potential of nanocarriers with controlled drug release and active targeting abilities.

Decoding Neurodegeneration: A Review of Molecular Mechanisms and Therapeutic Advances in Alzheimer's, Parkinson's, and ALS

Neurodegenerative diseases, such as Alzheimer's, Parkinson's, ALS, and Huntington's, remain formidable challenges in medicine, with their relentless progression and limited therapeutic options. These diseases arise from a web of molecular disturbances-misfolded proteins, chronic neuroinflammation, mitochondrial dysfunction, and genetic mutations-that slowly dismantle neuronal integrity. Yet, recent scientific breakthroughs are opening new paths to intervene in these once-intractable conditions. This review synthesizes the latest insights into the underlying molecular dynamics of neurodegeneration, revealing how intertwined pathways drive the course of these diseases. With an eye on the most promising advances, we explore innovative therapies emerging from cutting-edge research: nanotechnology-based drug delivery systems capable of navigating the blood-brain barrier, gene-editing tools like CRISPR designed to correct harmful genetic variants, and stem cell strategies that not only replace lost neurons but foster neuroprotective environments. Pharmacogenomics is reshaping treatment personalization, enabling tailored therapies that align with individual genetic profiles, while molecular diagnostics and biomarkers are ushering in an era of early, precise disease detection. Furthermore, novel perspectives on the gut-brain axis are sparking interest as mounting evidence suggests that microbiome modulation may play a role in reducing neuroinflammatory responses linked to neurodegenerative progression. Taken together, these advances signal a shift toward a comprehensive, personalized approach that could transform neurodegenerative care. By integrating molecular insights and innovative therapeutic techniques, this review offers a forward-looking perspective on a future where treatments aim not just to manage symptoms but to fundamentally alter disease progression, presenting renewed hope for improved patient outcomes.

Systemic treatment with a selective TNFR2 agonist alters the central and peripheral immune responses and transiently improves functional outcome after experimental ischemic stroke

Ischemic stroke often leaves survivors with permanent disabilities and therapies aimed at limiting detrimental inflammation and improving functional outcome are still needed. Tumor necrosis factor (TNF) levels increase rapidly after ischemic stroke, and while signaling through TNF receptor 1 (TNFR1) is primarily detrimental, TNFR2 signaling mainly has protective functions. We therefore investigated how systemic stimulation of TNFR2 with the TNFR2 agonist NewSTAR2 affects ischemic stroke in mice. We found that NewSTAR2 treatment induced changes in peripheral immune cell numbers and transiently affected microglial numbers and neuroinflammation. However, this was not sufficient to improve long-term functional outcome after stroke in mice.

Molecular and functional characteristics of receptor-interacting protein kinase 1 (RIPK1) and its therapeutic potential in Alzheimer's disease

Inflammation and cell death processes positively control the organ homeostasis of an organism. Receptor-interacting protein kinase 1 (RIPK1), a member of the RIPK family, is a crucial regulator of cell death and inflammation, and control homeostasis at the cellular and tissue level. Necroptosis, a programmed form of necrosis-mediated cell death and tumor necrosis factor (TNF)-induced necrotic cell death, is mostly regulated by RIPK1 kinase activity. Thus, RIPK1 has recently emerged as an upstream kinase that controls multiple cellular pathways and participates in regulating inflammation and cell death. All the major cell types in the central nervous system (CNS) have been found to express RIPK1. Selective inhibition of RIPK1 has been shown to prevent neuronal cell death, which could ultimately lead to a significant reduction of neurodegeneration and neuroinflammation. In addition, the kinase structure of RIPK1 is highly conducive to the development of specific pharmacological small-molecule inhibitors. These factors have led to the emergence of RIPK1 as an important therapeutic target for Alzheimer's disease (AD).

Data Mining of Microarray Datasets in Translational Neuroscience

Data mining involves the computational analysis of a plethora of publicly available datasets to generate new hypotheses that can be further validated by experiments for the improved understanding of the pathogenesis of neurodegenerative diseases. Although the number of sequencing datasets is on the rise, microarray analysis conducted on diverse biological samples represent a large collection of datasets with multiple web-based programs that enable efficient and convenient data analysis. In this review, we first discuss the selection of biological samples associated with neurological disorders, and the possibility of a combination of datasets, from various types of samples, to conduct an integrated analysis in order to achieve a holistic understanding of the alterations in the examined biological system. We then summarize key approaches and studies that have made use of the data mining of microarray datasets to obtain insights into translational neuroscience applications, including biomarker discovery, therapeutic development, and the elucidation of the pathogenic mechanisms of neurodegenerative diseases. We further discuss the gap to be bridged between microarray and sequencing studies to improve the utilization and combination of different types of datasets, together with experimental validation, for more comprehensive analyses. We conclude by providing future perspectives on integrating multi-omics, to advance precision phenotyping and personalized medicine for neurodegenerative diseases.

The TNFR1 antagonist Atrosimab reduces neuronal loss, glial activation and memory deficits in an acute mouse model of neurodegeneration

Tumor necrosis factor alpha (TNF-α) and its key role in modulating immune responses has been widely recognized as a therapeutic target for inflammatory and neurodegenerative diseases. Even though inhibition of TNF-α is beneficial for the treatment of certain inflammatory diseases, total neutralization of TNF-α largely failed in the treatment of neurodegenerative diseases. TNF-α exerts distinct functions depending on interaction with its two TNF receptors, whereby TNF receptor 1 (TNFR1) is associated with neuroinflammation and apoptosis and TNF receptor 2 (TNFR2) with neuroprotection and immune regulation. Here, we investigated the effect of administering the TNFR1-specific antagonist Atrosimab, as strategy to block TNFR1 signaling while maintaining TNFR2 signaling unaltered, in an acute mouse model for neurodegeneration. In this model, a NMDA-induced lesion that mimics various hallmarks of neurodegenerative diseases, such as memory loss and cell death, was created in the nucleus basalis magnocellularis and Atrosimab or control protein was administered centrally. We showed that Atrosimab attenuated cognitive impairments and reduced neuroinflammation and neuronal cell death. Our results demonstrate that Atrosimab is effective in ameliorating disease symptoms in an acute neurodegenerative mouse model. Altogether, our study indicates that Atrosimab may be a promising candidate for the development of a therapeutic strategy for the treatment of neurodegenerative diseases.

Discovery of novel CSF biomarkers to predict progression in dementia using machine learning

Providing an accurate prognosis for individual dementia patients remains a challenge since they greatly differ in rates of cognitive decline. In this study, we used machine learning techniques with the aim to identify cerebrospinal fluid (CSF) biomarkers that predict the rate of cognitive decline within dementia patients. First, longitudinal mini-mental state examination scores (MMSE) of 210 dementia patients were used to create fast and slow progression groups. Second, we trained random forest classifiers on CSF proteomic profiles and obtained a well-performing prediction model for the progression group (ROC-AUC = 0.82). As a third step, Shapley values and Gini feature importance measures were used to interpret the model performance and identify top biomarker candidates for predicting the rate of cognitive decline. Finally, we explored the potential for each of the 20 top candidates in internal sensitivity analyses. TNFRSF4 and TGF [Formula: see text]-1 emerged as the top markers, being lower in fast-progressing patients compared to slow-progressing patients. Proteins of which a low concentration was associated with fast progression were enriched for cell signalling and immune response pathways. None of our top markers stood out as strong individual predictors of subsequent cognitive decline. This could be explained by small effect sizes per protein and biological heterogeneity among dementia patients. Taken together, this study presents a novel progression biomarker identification framework and protein leads for personalised prediction of cognitive decline in dementia.

Activation of TNF Receptor 2 Improves Synaptic Plasticity and Enhances Amyloid-β Clearance in an Alzheimer's Disease Mouse Model with Humanized TNF Receptor 2

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) is a master cytokine involved in a variety of inflammatory and neurological diseases, including Alzheimer's disease (AD). Therapies that block TNF-α proved ineffective as therapeutic for neurodegenerative diseases, which might be explained by the opposing functions of the two receptors of TNF (TNFRs): while TNFR1 stimulation mediates inflammatory and apoptotic pathways, activation of TNFR2 is related to neuroprotection. Despite the success of targeting TNFR2 in a transgenic AD mouse model, research that better mimics the human context is lacking.

OBJECTIVE

The aim of this study is to investigate whether stimulation of TNFR2 with a TNFR2 agonist is effective in activating human TNFR2 and attenuating AD neuropathology in the J20xhuTNFR2-k/i mouse model.

METHODS

Transgenic amyloid-β (Aβ)-overexpressing mice containing a human extracellular TNFR2 domain (J20xhuTNFR2-k/i) were treated with a TNFR2 agonist (NewStar2). After treatment, different behavioral tests and immunohistochemical analysis were performed to assess different parameters, such as cognitive functions, plaque deposition, synaptic plasticity, or microglial phagocytosis.

RESULTS

Treatment with NewStar2 in J20xhuTNFR2-k/i mice resulted in a drastic decrease in plaque load and beta-secretase 1 (BACE-1) compared to controls. Moreover, TNFR2 stimulation increased microglial phagocytic activity, leading to enhanced Aβ clearance. Finally, activation of TNFR2 rescued cognitive impairments and improved synaptic plasticity.

CONCLUSION

Our findings demonstrate that activation of human TNFR2 ameliorates neuropathology and improves cognitive functions in an AD mouse model. Moreover, our study confirms that the J20xhuTNFR2-k/i mouse model is suitable for testing human TNFR2-specific compounds.

Fasting-mimicking diet cycles reduce neuroinflammation to attenuate cognitive decline in Alzheimer's models

The effects of fasting-mimicking diet (FMD) cycles in reducing many aging and disease risk factors indicate it could affect Alzheimer's disease (AD). Here, we show that FMD cycles reduce cognitive decline and AD pathology in E4FAD and 3xTg AD mouse models, with effects superior to those caused by protein restriction cycles. In 3xTg mice, long-term FMD cycles reduce hippocampal Aβ load and hyperphosphorylated tau, enhance genesis of neural stem cells, decrease microglia number, and reduce expression of neuroinflammatory genes, including superoxide-generating NADPH oxidase (Nox2). 3xTg mice lacking Nox2 or mice treated with the NADPH oxidase inhibitor apocynin also display improved cognition and reduced microglia activation compared with controls. Clinical data indicate that FMD cycles are feasible and generally safe in a small group of AD patients. These results indicate that FMD cycles delay cognitive decline in AD models in part by reducing neuroinflammation and/or superoxide production in the brain.

Phytochemicals as inhibitors of tumor necrosis factor alpha and neuroinflammatory responses in neurodegenerative diseases

Inflammatory processes and proinflammatory cytokines have a key role in the cellular processes of neurodegenerative diseases and are linked to the pathogenesis of functional and mental health disorders. Tumor necrosis factor alpha has been reported to play a major role in the central nervous system in Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis and many other neurodegenerative diseases. Therefore, a potent proinflammatory/proapoptotic tumor necrosis factor alpha could be a strong candidate for targeted therapy. Plant derivatives have now become promising candidates as therapeutic agents because of their antioxidant and chemical characteristics, and anti-inflammatory features. Recently, phytochemicals including flavonoids, terpenoids, alkaloids, and lignans have generated interest as tumor necrosis factor alpha inhibitor candidates for a number of diseases involving inflammation within the nervous system. In this review, we discuss how phytochemicals as tumor necrosis factor alpha inhibitors are a therapeutic strategy targeting neurodegeneration.

Cytokines and Transgenic Matrix in Autoimmune Diseases: Similarities and Differences

Autoimmune diseases are increasingly recognized as disease entities in which dysregulated cytokines contribute to tissue-specific inflammation. In organ-specific and multiorgan autoimmune diseases, the cytokine profiles show some similarities. Despite these similarities, the cytokines have different roles in the pathogenesis of different diseases. Altered levels or action of cytokines can result from changes in cell signaling. This article describes alterations in the JAK-STAT, TGF-β and NF-κB signaling pathways, which are involved in the pathogenesis of multiple sclerosis and systemic lupus erythematosus. There is a special focus on T cells in preclinical models and in patients afflicted with these chronic inflammatory diseases.

Conditional Ablation of Myeloid TNF Improves Functional Outcome and Decreases Lesion Size after Spinal Cord Injury in Mice

Spinal cord injury (SCI) is a devastating condition consisting of an instant primary mechanical injury followed by a secondary injury that progresses for weeks to months. The cytokine tumor necrosis factor (TNF) plays an important role in the pathophysiology of SCI. We investigated the effect of myeloid TNF ablation (peripheral myeloid cells (macrophages and neutrophils) and microglia) versus central myeloid TNF ablation (microglia) in a SCI contusion model. We show that TNF ablation in macrophages and neutrophils leads to reduced lesion volume and improved functional outcome after SCI. In contrast, TNF ablation in microglia only or TNF deficiency in all cells had no effect. TNF levels tended to be decreased 3 h post-SCI in mice with peripheral myeloid TNF ablation and was significantly decreased 3 days after SCI. Leukocyte and microglia populations and all other cytokines (IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, and IFNγ) and chemokines (CCL2, CCL5, and CXCL1) investigated, in addition to TNFR1 and TNFR2, were comparable between genotypes. Analysis of post-SCI signaling cascades demonstrated that the MAPK kinase SAPK/JNK decreased and neuronal Bcl-XL levels increased post-SCI in mice with ablation of TNF in peripheral myeloid cells. These findings demonstrate that peripheral myeloid cell-derived TNF is pathogenic in SCI.

Patients with obstructive sleep apnea have suppressed levels of soluble cytokine receptors involved in neurodegenerative disease, but normal levels with airways therapy

Purpose

Obstructive sleep apnea (OSA) results in systemic intermittent hypoxia. By one model, hypoxic stress signaling in OSA patients alters the levels of inflammatory soluble cytokines TNF and IL6, damages the blood brain barrier, and activates microglial targeting of neuronal cell death to increase the risk of neurodegenerative disorders and other diseases. However, it is not yet clear if OSA significantly alters the levels of the soluble isoforms of TNF receptors TNFR1 and TNFR2 and IL6 receptor (IL6R) and co-receptor gp130, which have the potential to modulate TNF and IL6 signaling.

Methods

Picogram per milliliter levels of the soluble isoforms of these four cytokine receptors were estimated in OSA patients, in OSA patients receiving airways therapy, and in healthy control subjects. Triplicate samples were examined using Bio-Plex fluorescent bead microfluidic technology. The statistical significance of cytokine data was estimated using the nonparametric Wilcoxon rank-sum test. The clustering of these high-dimensional data was visualized using t-distributed stochastic neighbor embedding (t-SNE).

Results

OSA patients had significant twofold to sevenfold reductions in the soluble serum isoforms of all four cytokine receptors, gp130, IL6R, TNFR1, and TNFR2, as compared with control individuals (p = 1.8 × 10⁻¹³ to 4 × 10⁻⁸). Relative to untreated OSA patients, airways therapy of OSA patients had significantly higher levels of gp130 (p = 2.8 × 10⁻¹³), IL6R (p = 1.1 × 10⁻⁹), TNFR1 (p = 2.5 × 10⁻¹⁰), and TNFR2 (p = 5.7 × 10⁻⁹), levels indistinguishable from controls (p = 0.29 to 0.95). The data for most airway-treated patients clustered with healthy controls, but the data for a few airway-treated patients clustered with apneic patients.

Conclusions

Patients with OSA have aberrantly low levels of four soluble cytokine receptors associated with neurodegenerative disease, gp130, IL6R, TNFR1, and TNFR2. Most OSA patients receiving airways therapy have receptor levels indistinguishable from healthy controls, suggesting a chronic intermittent hypoxia may be one of the factors contributing to low receptor levels in untreated OSA patients.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02205-y) contains supplementary material, which is available to authorized users.

Association of Tumor Necrosis Factor Receptor 1 Promoter Gene Polymorphisms (-580 A/G and -609 G/T) and TNFR1 Serum Levels with the Susceptibility to Gastric Precancerous Lesions and Gastric Cancer Related to H. pylori Infection in a Moroccan Population

Chronic inflammation due to H. pylori infection is the risk factor of gastric cancer (GC). Through its receptor (TNFR1), TNF-α plays a fundamental role in inflammatory, infectious, and tumor processes. Dysregulation of TNFR1 gene expression could impact many biological processes that can lead to cancer. This study is aimed at evaluating the association of TNFR1 promoter gene polymorphisms (-580 A/G and -609 G/T) and TNFR1 serum levels with GC and precancerous lesion susceptibility. Patients suffering from gastric lesions (65 chronic gastritis, 50 precancerous lesions, and 40 GC) related to H. pylori infection and 63 healthy controls (HC) were involved in this study. Individuals are genotyped by TNFR1 gene promoter sequencing, and TNFR1 serum levels were measured by the ELISA quantitative method. Concerning TNFR1 -609 G/T locus, we noticed that the T allele was associated with an attenuated susceptibility to GC (OR = 0.4; p value = 0.02). At the genotypic level and under the recessive model, the TNFR1 -609 TT genotype showed a decreased risk of GC (OR = 0.3, p value = 0.03) compared to the combined (GG/GT) genotypes. TNFR1 serum levels have been increased together with gastric lesion severity (p value < 0.05). The TNFR1 -609 TT genotype seemed linked to a low level of sTNFR1 compared to GT and GG genotypes (p value = 0.07). Concerning TNFR1 -580 A/G locus, no significant relation was noticed between this polymorphism and GC susceptibility, as well as with the TNFR1 serum level. Our results suggest that the TNFR1 -609 T allele appears to have a protective effect against GC. High levels of TNFR1 serum levels seemed to be associated with the aggressiveness of gastric lesions. Therefore, our results suggest that TNFR1 -609 T/G polymorphism and the TNFR1 serum levels may be related to GC susceptibility.

Tumor Necrosis Factor α Influences Phenotypic Plasticity and Promotes Epigenetic Changes in Human Basal Forebrain Cholinergic Neuroblasts

TNFα is the main proinflammatory cytokine implicated in the pathogenesis of neurodegenerative disorders, but it also modulates physiological functions in both the developing and adult brain. In this study, we investigated a potential direct role of TNFα in determining phenotypic changes of a recently established cellular model of human basal forebrain cholinergic neuroblasts isolated from the nucleus basalis of Meynert (hfNBMs). Exposing hfNBMs to TNFα reduced the expression of immature markers, such as nestin and β-tubulin III, and inhibited primary cilium formation. On the contrary, TNFα increased the expression of TNFα receptor TNFR2 and the mature neuron marker MAP2, also promoting neurite elongation. Moreover, TNFα affected nerve growth factor receptor expression. We also found that TNFα induced the expression of DNA-methylation enzymes and, accordingly, downregulated genes involved in neuronal development through epigenetic mechanisms, as demonstrated by methylome analysis. In summary, TNFα showed a dual role on hfNBMs phenotypic plasticity, exerting a negative influence on neurogenesis despite a positive effect on differentiation, through mechanisms that remain to be elucidated. Our results help to clarify the complexity of TNFα effects in human neurons and suggest that manipulation of TNFα signaling could provide a potential therapeutic approach against neurodegenerative disorders.

The multi-faceted impact of methamphetamine on Alzheimer's disease: From a triggering role to a possible therapeutic use

Although it has been initially synthesized for therapeutic purposes and currently FDA-approved and prescribed for obesity, attention-deficit/hyperactivity disorder, narcolepsy and depression, methamphetamine became a recreational drug that is nowadays massively manufactured illegally. Because it is a powerful and extremely addictive psychotropic agent, its abuse has turned out to become a major health problem worldwide. Importantly, the numerous effects triggered by this drug induce neurotoxicity in the brain ultimately leading to serious neurological impairments, tissue damage and neuropsychological disturbances that are reminiscent to most of the symptoms observed in Alzheimer's disease and other pathological manifestations in aging brain. In this context, there is a growing number of compelling evidence linking methamphetamine abuse with a higher probability of developing premature Alzheimer's disease and consequent neurodegeneration. This review proposes to establish a broad assessment of the effects that this drug can generate at the cellular and molecular levels in connection with the development of the age-related Alzheimer's disease. Altogether, the objective is to warn against the long-term effects that methamphetamine abuse may convey on young consumers and the increased risk of developing this devastating brain disorder at later stages of their lives, but also to discuss a more recently emerging concept suggesting a possible use of methamphetamine for treating this pathology under proper and strictly controlled conditions.

Role of Pro-inflammatory Cytokines in Regulation of Skeletal Muscle Metabolism: A Systematic Review

Background:

Metabolic pathways perturbations lead to skeletal muscular atrophy in the cachexia and sarcopenia due to increased catabolism. Pro-inflammatory cytokines induce the catabolic pathways that impair the muscle integrity and function. Hence, this review primarily concentrates on the effects of pro-inflammatory cytokines in regulation of skeletal muscle metabolism.

Objective:

This review will discuss the role of pro-inflammatory cytokines in skeletal muscles during muscle wasting conditions. Moreover, the coordination among the pro-inflammatory cytokines and their regulated molecular signaling pathways which increase the protein degradation will be discussed.

Results:

During normal conditions, pro-inflammatory cytokines are required to balance anabolism and catabolism and to maintain normal myogenesis process. However, during muscle wasting their enhanced expression leads to marked destructive metabolism in the skeletal muscles. Proinflammatory cytokines primarily exert their effects by increasing the expression of calpains and E3 ligases as well as of Nf-κB, required for protein breakdown and local inflammation. Proinflammatory cytokines also locally suppress the IGF-1and insulin functions, hence increase the FoxO activation and decrease the Akt function, the central point of carbohydrates lipid and protein metabolism.

Conclusion:

Current advancements have revealed that the muscle mass loss during skeletal muscular atrophy is multifactorial. Despite great efforts, not even a single FDA approved drug is available in the market. It indicates the well-organized coordination among the pro-inflammatory cytokines that need to be further understood and explored.

Microemulsion co-delivering vitamin A and vitamin E as a new platform for topical treatment of acute skin inflammation

In this study, we developed a water-in-oil microemulsion containing vitamin A (retinol) and vitamin E (α-tocopherol), which serves as a multifunctional nanosystem that co-delivers antioxidants and displayed additive effect against acute skin inflammation. Microemulsion (ME) was prepared by mixing a surfactant blend (Tween 80 and propylene glycol, 5:1) with isopropyl myristate and water (ratio of 50:40:10, respectively). Vitamin A (0.05% w/w concentration) and/or vitamin E (0.1% w/w concentration) were incorporated into the surfactant mixture of ME by stirring with a magnetic stirrer for 30 min. This multifunctional ME displayed physical stability, with low cytotoxicity in 3T3 cell line, as well as cellular internalization into the cytosol. In vivo treatments using ME delivering α-tocopherol reduced dermal expression of TNF-α by 1.3-fold (p < 0.01), when compared to unloaded ME treatment group. When retinol was added into the ME containing α-tocopherol, it further reduced TNF-α expression by 2-fold (p < 0.001), suggesting the additive effect of vitamin E and vitamin A in the treatment against skin inflammation. In conclusion, we successfully developed the use of water-in-oil ME to pack both vitamin E and vitamin A, and demonstrated for the first time its anti-inflammatory potential when applied topically to TPA-induced inflamed skin.

Lipocalin-2: Its perspectives in brain pathology and possible roles in cognition

Lipocalin-2 (LCN2) has been known to play an important role in pathological conditions, specifically in response to inflammation, infection and injury to cells. Recently, several research teams have been interested in investigating its association with cognition during the progression of pathology. Previous studies have demonstrated that LCN2 is not correlated with cognitive function under normal physiological conditions, although LCN2 has been negatively associated with cognition and some neuropathologies. Increasing LCN2 production is associated with reduced cognitive performance in a rodent model. However, further studies are needed to explore the potential underlying mechanisms of LCN2 on cognitive dysfunction, as well as its clinical relevance. This review aims to summarise the evidence available from in vitro, in vivo and clinical studies concerning the possible role of LCN2 on cognitive function following the onset of pathological conditions. Any contradictory evidence is also assessed and presented.

Cell Death Pathways: a Novel Therapeutic Approach for Neuroscientists

In the first part, the following mechanisms involved in different forms of cell death are considered, with a view to identifying potential therapeutic targets: tumour necrosis factor receptors (TNFRs) and their engagement by tumour necrosis factor-alpha (TNF-α); poly [ADP-ribose] polymerase (PARP)-1 cleavage; the apoptosis signalling kinase (ASK)-c-Jun N-terminal kinase (JNK) axis; lysosomal permeability; activation of programmed necrotic cell death; oxidative stress, caspase-3 inhibition and parthanatos; activation of inflammasomes by reactive oxygen species and the development of pyroptosis; oxidative stress, calcium dyshomeostasis and iron in the development of lysosomal-mediated necrosis and lysosomal membrane permeability; and oxidative stress, lipid peroxidation, iron dyshomeostasis and ferroptosis. In the second part, there is a consideration of the role of lethal and sub-lethal activation of these pathways in the pathogenesis and pathophysiology of neurodegenerative and neuroprogressive disorders, with particular reference to the TNF-α-TNFR signalling axis; dysregulation of ASK-1-JNK signalling; prolonged or chronic PARP-1 activation; the role of pyroptosis and chronic inflammasome activation; and the roles of lysosomal permeabilisation, necroptosis and ferroptosis. Finally, it is suggested that, in addition to targeting oxidative stress and inflammatory processes generally, neuropsychiatric disorders may respond to therapeutic targeting of TNF-α, PARP-1, the Nod-like receptor NLRP3 inflammasome and the necrosomal molecular switch receptor-interacting protein kinase-3, since their widespread activation can drive and/or exacerbate peripheral inflammation and neuroinflammation even in the absence of cell death. To this end, the use is proposed of a combination of the tetracycline derivative minocycline and N-acetylcysteine as adjunctive treatment for a range of neuropsychiatric disorders.

Selective Modulation of TNF-TNFRs Signaling: Insights for Multiple Sclerosis Treatment

Autoimmunity develops when self-tolerance mechanisms are failing to protect healthy tissue. A sustained reaction to self is generated, which includes the generation of effector cells and molecules that destroy tissues. A way to restore this intrinsic tolerance is through immune modulation that aims at refurbishing this immunologically naïve or unresponsive state, thereby decreasing the aberrant immune reaction taking place. One major cytokine has been shown to play a pivotal role in several autoimmune diseases such as rheumatoid arthritis (RA) and multiple sclerosis (MS): tumor necrosis factor alpha (TNFα) modulates the induction and maintenance of an inflammatory process and it comes in two variants, soluble TNF (solTNF) and transmembrane bound TNF (tmTNF). tmTNF signals via TNFR1 and TNFR2, whereas solTNF signals mainly via TNFR1. TNFR1 is widely expressed and promotes mainly inflammation and apoptosis. Conversely, TNFR2 is restricted mainly to immune and endothelial cells and it is known to activate the pro-survival PI3K-Akt/PKB signaling pathway and to sustain regulatory T cells function. Anti-TNFα therapies are successfully used to treat diseases such as RA, colitis, and psoriasis. However, clinical studies with a non-selective inhibitor of TNFα in MS patients had to be halted due to exacerbation of clinical symptoms. One possible explanation for this failure is the non-selectivity of the treatment, which avoids TNFR2 stimulation and its immune and tissue protective properties. Thus, a receptor-selective modulation of TNFα signal pathways provides a novel therapeutic concept that might lead to new insights in MS pathology with major implications for its effective treatment.

Novel strategies to mimic transmembrane tumor necrosis factor-dependent activation of tumor necrosis factor receptor 2

Tumor necrosis factor receptor 2 (TNFR2) is known to mediate immune suppression and tissue regeneration. Interestingly, the transmembrane form of tumor necrosis factor (tmTNF) is necessary to robustly activate TNFR2. To characterize the stoichiometry and composition of tmTNF during TNFR2 activation, we constructed differently oligomerized single chain TNF ligands (scTNF) comprised of three TNF homology domain (THD) protomers that mimic tmTNF. Using a variety of cellular and in vivo assays, we can show that higher oligomerization of the scTNF trimers results in more efficient TNF/TNFR2 clustering and subsequent signal transduction. Importantly, the three-dimensional orientation of the scTNF trimers impacts the bioactivity of the oligomerized scTNF ligands. Our data unravel the organization of tmTNF-mimetic scTNF ligands capable of robustly activating TNFR2 and introduce novel TNFR2 agonists that hold promise as therapeutics to treat a variety of diseases.

Tumor Necrosis Factor-Alpha: Role in Development of Insulin Resistance and Pathogenesis of Type 2 Diabetes Mellitus

Pathogenesis of type 2 diabetes mellitus (T2DM) and development of insulin resistance are characterized by multi-stimuli factors notably glucolipotoxicity, generation of reactive oxygen species (ROS), epigenetic factors, activation of various transcriptional mediated pathways along with the augmented levels of various pro-inflammatory cytokines. Among the various pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-α) is one the most important pro-inflammatory mediator that is critically involved in the development of insulin resistance and pathogenesis of T2DM. TNF-α is mainly produced in adipocytes and/or peripheral tissues, and induces tissue-specific inflammation through the involvement of generation of ROS and activation of various transcriptional mediated pathways. The raised level of TNF-α induces insulin resistance in adipocytes and peripheral tissues by impairing the insulin signaling through serine phosphorylation that leads to the development of T2DM. Anti-TNF-α treatment strategies have been developed to reduce the incidence of insulin resistance and development of T2DM. In this article, we have briefly described how TNF-α plays crucial role to induce insulin resistance and pathogenesis of T2DM. To block the inflammatory responses by blocking TNF-α and TNF-α signaling may be an effective strategy for the treatment of insulin resistance and T2DM. J. Cell. Biochem. 119: 105-110, 2018. © 2017 Wiley Periodicals, Inc.

Essential protective role of tumor necrosis factor receptor 2 in neurodegeneration

Despite the recognized role of tumor necrosis factor (TNF) in inflammation and neuronal degeneration, anti-TNF therapeutics failed to treat neurodegenerative diseases. Animal disease models had revealed the antithetic effects of the two TNF receptors (TNFR) in the central nervous system, whereby TNFR1 has been associated with inflammatory degeneration and TNFR2 with neuroprotection. We here show the therapeutic potential of selective inhibition of TNFR1 and activation of TNFR2 by ATROSAB, a TNFR1-selective antagonistic antibody, and EHD2-scTNF_R2, an agonistic TNFR2-selective TNF, respectively, in a mouse model of NMDA-induced acute neurodegeneration. Coadministration of either ATROSAB or EHD2-scTNF_R2 into the magnocellular nucleus basalis significantly protected cholinergic neurons and their cortical projections against cell death, and reverted the neurodegeneration-associated memory impairment in a passive avoidance paradigm. Simultaneous blocking of TNFR1 and TNFR2 signaling, however, abrogated the therapeutic effect. Our results uncover an essential role of TNFR2 in neuroprotection. Accordingly, the therapeutic activity of ATROSAB is mediated by shifting the balance of the antithetic activity of endogenous TNF toward TNFR2, which appears essential for neuroprotection. Our data also explain earlier results showing that complete blocking of TNF activity by anti-TNF drugs was detrimental rather than protective and argue for the use of next-generation TNFR-selective TNF therapeutics as an effective approach in treating neurodegenerative diseases.