Activation of IKKalpha target genes depends on recognition of specific kappaB binding sites by RelB:p52 dimers

PDK1-mediated phosphorylation of USP5 modulates NF-κB signalling to enhance osteosarcoma growth

The overexpression of pyruvate dehydrogenase kinase 1 (PDK1) has been observed in a number of different cancers, making it a potential target for the treatment of cancer. In this study, we used bioinformatics methods to analyse the immunophenotype of osteosarcoma (OS) and identified PDK1 as a critical factor in the different immune states of the disease. A pan-cancer analysis revealed a robust correlation between PDK1 and the tumour microenvironment. Moreover, our findings corroborate the overexpression of PDK1 in OS, whereby it facilitates tumour development via the NF-κB pathway. From a mechanistic perspective, PDK1 has the capacity to bind and phosphorylate USP5. The phosphorylation of USP5 by PDK1 activates its deubiquitinating activity, leading to the stabilisation of IKKγ protein and subsequent activation of the NF-κB signalling pathway, which ultimately promotes the growth of OS cells. Molecular simulation docking, pull-down assays, and SIP experiments were employed to further identify arctigenin (ATG) as a small molecule inhibitor of PDK1. The findings demonstrated that ATG effectively inhibited the growth of OS cells and tumour xenograft models. Collectively, these results highlight that PDK1 influences NF-κB in OS through the PDK1-USP5-IKKγ axis. Furthermore, the identification of ATG as an effective inhibitor of PDK1 suggests that ATG may serve as a promising lead compound for the treatment of OS.

Vitamin D receptor signalling regulates the diet-driven metabolic shift during weaning

OBJECTIVE

Weaning in mammals is associated with a shift in the metabolism, driven by the differences in the macronutrient composition of milk and post-weaning diet. Milk has a higher fat content compared with the carbohydrate-enriched solid food. Malnutrition during this stage could affect this transition with long-term adverse effects. The role of micronutrients during this transition is not well understood.

METHODS

We used mice lacking a functional vitamin D receptor (VDR) to study the role of vitamin D signalling in the metabolic transition during weaning.

RESULTS

We demonstrate that after weaning, VDR knockout mice exhibit systemic energy deprivation and higher lipolysis in inguinal white adipose tissue, probably due to increased norepinephrine signalling via protein kinase A (PKA) and extracellular signalling-regulated kinase (ERK) pathways. The energy deprivation in vdr-/- mice is associated with defective liver glycogenolysis, characterized by increased expression of protein phosphatase-1 alpha and decreased glycogen phosphorylase activity. However, restoration of serum calcium and phosphate levels by a rescue diet is sufficient to restore energy metabolism in vdr-/- mice. Interestingly, maintaining a high-fat-containing milk-based diet post-weaning could prevent the onset of energy deprivation, liver glycogen storage defect, and adipose atrophy in these mice.

CONCLUSION

Our data show that vitamin D-signalling is essential for the adaptation of mice to the dietary shift from high-fat-containing milk to post-weaning carbohydrate-enriched diets. It also reveals a novel macronutrient-micronutrient interaction that shapes the metabolic flexibility of the individual based on the dietary composition of nutrients.

Melatonin and retinal cell damage: molecular and biological functions

The indoleamine hormone, melatonin, is produced in the pineal gland and has an essential role in many physiological functions. The pineal gland is considered to be the most important organ for producing melatonin. Nevertheless, it is important to point out that the eye is also capable of producing melatonin, and has its own circadian rhythm in producing this hormone. Melatonin is mainly produced by a subpopulation of photoreceptors in a diurnal rhythm. Numerous in vitro and in vivo studies have shown the beneficial effects of melatonin in eye-related disorders. These diseases primarily affect retinal cells, highlighting the therapeutic potential of melatonin, especially in the retina. Melatonin's ability to regulate oxidative stress response pathways and modulate the expression of antioxidant genes makes it a promising candidate for mitigating retinal cell damage. Moreover, melatonin can modulate inflammatory pathways such as NF-кB and further reduce retinal damage, as well as affecting programmed cell death such as apoptosis and autophagy in retinal cells. Therefore, the goal of this review is to explore the ways in which melatonin protects retinal cells from damage and ischemia. We discuss the mechanisms involved in order to gain valuable understanding of the possible therapeutic applications of melatonin in protection of retinal cells and treatment of retinal disorders.

NF-κB RelB suppresses the inflammatory gene expression programs of dendritic cells by competing with RelA for binding to target gene promoters

A group of autoinflammatory disorders termed relopathies arise as a consequence of NF-κB dysregulation. Genetic loss of the NF-κB subunit RelB in humans and mice leads to autoimmunity and lethal multi-organ inflammatory pathology. Our recent study showed that this inflammatory pathology is independent of type I interferon signaling, and further identified dysregulation of a set of pro-inflammatory NF-κB target genes. However, it remains unknown how the loss of RelB leads to the dysregulation of these NF-κB motif-containing pro-inflammatory genes. Here, we report epigenome profiling studies revealing that RelB is associated with pro-inflammatory genes in dendritic cells. While these genes recruit RelA binding upon exposure to a maturation stimulus, we observed substantially more RelA recruitment in the absence of RelB. For these genes, we found that elevated RelA recruitment is correlated with elevated gene expression. To test whether RelB may compete with RelA for binding to NF-κB-regulated gene promoters via competition for κB sites, we generated a new mouse strain (RelBDB/DB) that harbors targeted point mutations in the RelB DNA binding domain that eliminates high-affinity DNA binding. We found that this targeted mutation in the RelB DNA binding domain is sufficient to drive multi-organ inflammatory pathology. These results provide insights into the biological mechanism of RelB as a suppressor of pro-inflammatory gene expression and autoimmune pathology.

The effect of selenium on the intestinal health of juvenile grass carp based on the ERS-autophagy pathway

Selenium (Se), a trace element, is vital for the maintenance of cellular redox balance, thyroid hormone metabolism, inflammation, and immunity. Aeromonas hydrophila (A. hydrophila) is a common Gram-negative conditional pathogenic bacterium in fish culture, posing a serious threat to intensive aquaculture. Our study investigated the influence of dietary Se on the intestinal immune function of grass carp (Ctenopharyngodon idella) and the related regulatory mechanisms. The 2160 healthy juvenile grass carp (9.76 ± 0.005 g) were randomly assigned to 6 test groups of 6 replicates each, and fed graded selenomethionine (0.05, 0.20, 0.40, 0.61, 0.77, 0.98 mg Se/kg diet) for 70 days and then injected with A. hydrophila for a 6-day attack test. The results indicated that appropriate Se levels (0.40 mg/kg diet) alleviated intestinal damage caused by A. hydrophila and increased intestinal immune substances C3 and C4 levels as well as the activity of acid phosphatase (ACP) and lysozyme (LZ) (P > 0.05). Appropriate levels of Se (0.40 mg/kg-0.61 mg/kg diet) decreased intestinal pro-inflammatory cytokines (IFN-γ2, IL-6, IL-12p35, IL-17 A F and IL-17D) mRNA levels (P > 0.05) and increased intestinal anti-inflammatory factors (TGF-β1, IL-4/13A, IL-4/13B, IL-10 and IL-22) mRNA levels (P > 0.05) in juvenile grass carp. Further studies revealed that Se (0.40 mg/kg-0.61 mg/kg diet) inhibited intestinal endoplasmic reticulum stress (ERS)-related signaling pathway. Furthermore, we found that appropriate levels of Se (0.40 mg/kg-0.61 mg/kg diet) inhibited intestinal autophagy in juvenile grass carp, which may be related to ULK1, Beclin 1, ATG5, ATG12, LC3, and P62. In conclusion, appropriate levels of Se can alleviate intestinal inflammation and inhibit ERS and autophagy in juvenile grass carp. A quadratic regression analysis of intestinal ACP and LZ also indicated that the Se requirements of juvenile grass carp were 0.59 and 0.51 mg/kg, respectively.

The role of NF-κB-SOX9 signalling pathway in osteoarthritis

The nuclear factor-κB (NF-κB) signalling pathway exists in a variety of cells and is involved in the gene regulation of various physiological and pathological processes such as inflammation, immunity, cell proliferation and apoptosis. It has been shown that this signaling pathway is also involved in numerous events associated with osteoarthritis, including chondrocyte catabolism, chondrocyte survival, and synovial inflammation. SRY-related high mobility group-box 9(SOX9) is the "master regulator" of chondrocytes and one of the key transcription factors that maintain chondrocyte phenotype and cartilage homeostasis. NF-κB can positively regulate the expression of SOX9 by directly binding to its promoter region, and play a role in the formation and development of chondrocytes. This article reviews the regulatory effect of the NF-κB-SOX9 signaling axis on osteoarthritis.

The regulating effect of curcumin on NF-κB pathway in neurodegenerative diseases: a review of the underlying mechanisms

Neurodegenerative diseases are part of the central nervous system (CNS) disorders that indicate their presence with neuronal loss, neuroinflammation, and increased oxidative stress. Several pathophysiological factors and biomarkers are involved in this inflammatory process causing these neurological disorders. The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is an inflammation element, which induced transcription and appears to be one of the important players in physiological procedures, especially nervous disorders. NF-κB can impact upon series of intracellular actions and induce or inhibit many inflammation-related pathways. Multiple reports have focused on the modification of NF-κB activity, controlling its expression, translocation, and signaling pathway in neurodegenerative disorders and injuries like Alzheimer's disease (AD), spinal cord injuries (SCI), and Parkinson's disease (PD). Curcumin has been noted to be a popular anti-oxidant and anti-inflammatory substance and is the foremost natural compound produced by turmeric. According to various studies, when playing an anti-inflammatory role, it interacts with several modulating proteins of long-standing disease signaling pathways and has an unprovocative consequence on pro-inflammatory cytokines. This review article determined to figure out curcumin's role in limiting the promotion of neurodegenerative disease via influencing the NF-κB signaling route. Preclinical studies were gathered from plenty of scientific platforms including PubMed, Scopus, Cochrane, and Google Scholar to evaluate this hypothesis. Extracted findings from the literature review explained the repressing impact of Curcumin on the NF-κB signaling pathway and, occasionally down-regulating the cytokine expression. Yet, there is an essential need for further analysis and specific clinical experiments to fully understand this subject.

The role of Sirtuin 2 in liver - An extensive and complex biological process

Liver disease has become one of the main causes of health issue worldwide. Sirtuin (Sirt) 2 is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase, and is expressed in multiple organs including liver, which plays important and complex roles by interacting with various substrates. Physiologically, Sirt2 can improve metabolic homeostasis. Pathologically, Sirt2 can alleviate inflammation, endoplasmic reticulum (ER) stress, promote liver regeneration, maintain iron homeostasis, aggravate fibrogenesis and regulate oxidative stress in liver. In liver diseases, Sirt2 can mitigate fatty liver disease (FLD) including non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD), but aggravate hepatitis B (HBV) and liver ischemia-reperfusion injury (LIRI). The role of Sirt2 in liver cancer and aging-related liver diseases, however, has not been fully elucidated. In this review, these biological processes regulated by Sirt2 in liver are summarized, which aims to update the function of Sirt2 in liver and to explore the potential role of Sirt2 as a therapeutic target for liver diseases.

Highly cyto- and immune compatible new synthetic fluorapatite nanomaterials co-doped with rubidium(I) and europium(III) ions

In the present study, biocompatible luminescent of nanosized fluorapatite doped with rubidium(I) (Rb+ ion) and europium(III) (Eu3+ ion) ions were synthesized via hydrothermal method. It was investigated the influence of co-doped Rb+ and Eu3+ ions on the structural, and morphological characteristics of the obtained fluorapatite materials. The characterization techniques utilized included: X-ray powder diffraction (XRPD), infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Moreover, to establish the influence of the co-doped Rb+ and Eu3+ ions on the luminescence properties of the lanthanide ion, emission excitation, emission spectrum and luminescence decays were measured. This confirmed a distinct red emission originating from Eu3+ ions and an increased emission lifetime. To determine the biocompatibility of the obtained fluorapatite compounds, in vitro studies using normal dermal human fibroblasts were performed. The results of these studies clearly demonstrate the remarkable biocompatibility of our compounds. This discovery opens exciting prospects for the use of synthetic fluorapatites doped with Eu3+ and Rb+ ions in various biomedical contexts. In particular, these materials hold great promise for potential applications in regenerative engineering, but also serve as innovative and practical solutions as bone scaffolds and dental implants containing nano-fluorapatite. Further discussion of these properties can be found in this article, along with a discussion of their importance and potential in the field of biomedical applications. However, according to our pervious study and based on our current investigations but also based on available scientific records, it was proposed potential molecular mechanism of Rb+ ions in the process of osteoclastogenesis.

TRIM55 promotes noncanonical NF-κB signaling and B cell-mediated immune responses by coordinating p100 ubiquitination and processing

The ubiquitination-dependent processing of NF-κB2 (also known as p100) is a critical step in the activation of the noncanonical NF-κB pathway. We investigated the molecular mechanisms regulating this process and showed that TRIM55 was the E3 ubiquitin ligase that mediated the ubiquitination of p100 and coordinated its processing. TRIM55 deficiency impaired noncanonical NF-κB activation and B cell function. Mice with a B cell-specific Trim55 deficiency exhibited reduced germinal center formation and antibody production. These mice showed less severe symptoms than those of control mice upon the induction of a systemic lupus-like disease, suggesting B cell-intrinsic functions of TRIM55 in humoral immune responses and autoimmunity. Mechanistically, the ubiquitination of p100 mediated by TRIM55 was crucial for p100 processing by VCP, an ATPase that mediates ubiquitin-dependent protein degradation by the proteasome. Furthermore, we found that TRIM55 facilitated the interaction between TRIM21 and VCP as well as TRIM21-mediated K63-ubiquitination of VCP, both of which were indispensable for the formation of the VCP-UFD1-NPL4 complex and p100 processing. Together, our results reveal a mechanism by which TRIM55 fine-tunes p100 processing and regulates B cell-dependent immune responses in vivo, highlighting TRIM55 as a potential therapeutic target for lupus-like disease.

Probing the links: Long non-coding RNAs and NF-κB signalling in atherosclerosis

Atherosclerosis is a chronic inflammatory disease that involves the accumulation of lipids and immune cells in the arterial wall. NF-kB signaling is a key regulator of inflammation and is known to play a critical role in atherosclerosis. Recent studies have shown that lncRNAs can regulate NF-kB and contribute to the development and progression of atherosclerosis. Preliminary findings reveal significant alterations in the expression of specific lncRNAs in atherosclerotic lesions compared to healthy arterial tissue. Experimental evidence suggests that these dysregulated lncRNAs can influence the NF-kB pathway. By unravelling the crosstalk between lncRNAs and NF-kB signaling, this review aims to enhance our understanding of the molecular mechanisms underlying atherosclerosis. Identifying novel therapeutic targets and diagnostic markers may lead to developing interventions and management strategies for this prevalent cardiovascular disease. This review summarizes the current knowledge on the role of lncRNAs in NF-kB signaling in atherosclerosis and highlights their potential as therapeutic targets for this disease.

Dysbindin Domain-Containing 1 in Prostate Cancer: New Insights into Bioinformatic Validation of Molecular and Immunological Features

Prostate cancer (PCa) is one of the most prevalent cancers in men, yet its pathogenic pathways remain poorly understood. Transcriptomics and high-throughput sequencing can help uncover cancer diagnostic targets and understand biological circuits. Using prostate adenocarcinoma (PRAD) datasets of various web-based applications (GEPIA, UALCAN, cBioPortal, SR Plot, hTFtarget, Genome Browser, and MetaCore), we found that upregulated dysbindin domain-containing 1 (DBNDD1) expression in primary prostate tumors was strongly correlated with pathways involving the cell cycle, mitotic in KEGG, WIKI, and REACTOME database, and transcription factor-binding sites with the DBNDD1 gene in prostate samples. DBNDD1 gene expression was influenced by sample type, cancer stage, and promoter methylation levels of different cancers, such as PRAD, liver hepatocellular carcinoma (LIHC), and lung adenocarcinoma (LUAD). Regulation of glycogen synthase kinase (GSK)-3β in bipolar disorder and ATP/ITP/GTP/XTP/TTP/CTP/UTP metabolic pathways was closely correlated with the DBNDD1 gene and its co-expressed genes in PCa. DBNDD1 gene expression was positively associated with immune infiltration of B cells, Myeloid-derived suppressor cell (MDSC), M2 macrophages, andneutrophil, whereas negatively correlated with CD8+ T cells, T follicular helper cells, M1 macrophages, and NK cells in PCa. These findings suggest that DBNDD1 may serve as a viable prognostic marker not only for early-stage PCa but also for immunotherapies.

Alternative Splicing of RIOK3 Engages the Noncanonical NFκB Pathway during Rift Valley Fever Virus Infection

Although the noncanonical NFκB pathway was originally identified as a cellular pathway contributing to lymphoid organogenesis, in the past 20 years, its involvement in innate immunity has become more appreciated. In particular, the noncanonical NFκB pathway has been found to be activated and even exploited by some RNA viruses during infection. Intriguingly, activation of this pathway has been shown to have a role in disrupting transcription of type 1 interferon (IFN), suggesting a rationale for why this response could be co-opted by some viruses. Rift Valley fever virus (RVFV) is a trisegmented ambisense RNA virus that poses a considerable threat to domestic livestock and human health. Previously, we showed the atypical kinase RIOK3 is important for mounting an IFN response to RVFV infection of human epithelial cells, and shortly following infection with RVFV (MP12 strain), RIOK3 mRNA is alternatively spliced to its X2 isoform that encodes a truncated RIOK3 protein. Alternative splicing of RIOK3 mRNA has an inhibitory effect on the IFN response but also stimulates an NFκB-mediated inflammatory response. Here, we demonstrate alternative splicing of RIOK3 mRNA is associated with activation of the noncanonical NFκB pathway and suggest this pathway is co-opted by RVFV (MP12) to enhance viral success during infection.

NF-kB's contribution to B cell fate decisions

NF-κB signaling is essential to an effective innate and adaptive immune response. Many immune-specific functional and developmental outcomes depend in large on NF-κB. The formidable task of sorting out the mechanisms behind the regulation and outcome of NF-κB signaling remains an important area of immunology research. Here we briefly discuss the role of NF-κB in regulating cell fate decisions at various times in the path of B cell development, activation, and the generation of long-term humoral immunity.

NF-κB-Inducing Kinase Provokes Insulin Resistance in Skeletal Muscle of Obese Mice

Skeletal muscle is crucial for preserving glucose homeostasis. Insulin resistance and abnormalities in glucose metabolism result from a range of pathogenic factors attacking skeletal muscle in obese individuals. To relieve insulin resistance and restore glucose homeostasis, blocking the cell signaling pathways induced by those pathogenic factors seems an attractive strategy. It has been discovered that insulin sensitivity in obese people is inversely linked with the activity of NF-κB inducing kinase (NIK) in skeletal muscle. In order to evaluate NIK's pathological consequences, mechanism of action, and therapeutic values, an obese mouse model reproduced by feeding a high-fat diet was treated with a NIK inhibitor, B022. C2C12 myoblasts overexpressing NIK were utilized to assess insulin signaling and glucose uptake. B022 thus prevented high-fat diet-induced NIK activation and insulin desensitization in skeletal muscle. The insulin signaling in C2C12 myoblasts was compromised by the upregulation of NIK brought on by oxidative stress, lipid deposition, inflammation, or adenoviral vector. This inhibition of insulin action is mostly due to an inhibitory serine phosphorylation of IRS1 caused by ERK, JNK, and PKC that were activated by NIK. In summary, NIK integrates signals from several pathogenic factors to impair insulin signaling by igniting a number of IRS1-inhibiting kinases, and it also has significant therapeutic potential for treating insulin resistance.

The NF-κB Transcriptional Network Is a High-Dose Vitamin C-Targetable Vulnerability in Breast Cancer

Breast cancer (BC) is the most common cancer type among women with a distinct clinical presentation, but the survival rate remains moderate despite advances in multimodal therapy. Consequently, a deeper understanding of the molecular etiology is required for the development of more effective treatments for BC. The relationship between inflammation and tumorigenesis is well established, and the activation of the pro-inflammatory transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is frequently identified in BC. Constitutive NF-κB activation is linked to cell survival, metastasis, proliferation, and hormonal, chemo-, and radiotherapy resistance. Moreover, the crosstalk between NF-κB and other transcription factors is well documented. It is reported that vitamin C plays a key role in preventing and treating a number of pathological conditions, including cancer, when administered at remarkably high doses. Indeed, vitamin C can regulate the activation of NF-κB by inhibiting specific NF-κB-dependent genes and multiple stimuli. In this review, we examine the various NF-κB impacts on BC development. We also provide some insight into how the NF-κB network may be targeted as a potential vulnerability by using natural pro-oxidant therapies such as vitamin C.

Functions of the aryl hydrocarbon receptor (AHR) beyond the canonical AHR/ARNT signaling pathway

The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor regulating adaptive and maladaptive responses toward exogenous and endogenous signals. Research from various biomedical disciplines has provided compelling evidence that the AHR is critically involved in the pathogenesis of a variety of diseases and disorders, including autoimmunity, inflammatory diseases, endocrine disruption, premature aging and cancer. Accordingly, AHR is considered an attractive target for the development of novel preventive and therapeutic measures. However, the ligand-based targeting of AHR is considerably complicated by the fact that the receptor does not always follow the beaten track, i.e. the canonical AHR/ARNT signaling pathway. Instead, AHR might team up with other transcription factors and signaling molecules to shape gene expression patterns and associated physiological or pathophysiological functions in a ligand-, cell- and micromilieu-dependent manner. Herein, we provide an overview about some of the most important non-canonical functions of AHR, including crosstalk with major signaling pathways involved in controlling cell fate and function, immune responses, adaptation to low oxygen levels and oxidative stress, ubiquitination and proteasomal degradation. Further research on these diverse and exciting yet often ambivalent facets of AHR biology is urgently needed in order to exploit the full potential of AHR modulation for disease prevention and treatment.

CXCL13-CXCR5 axis: Regulation in inflammatory diseases and cancer

Chemokine C-X-C motif ligand 13 (CXCL13), originally identified as a B-cell chemokine, plays an important role in the immune system. The interaction between CXCL13 and its receptor, the G-protein coupled receptor (GPCR) CXCR5, builds a signaling network that regulates not only normal organisms but also the development of many diseases. However, the precise action mechanism remains unclear. In this review, we discussed the functional mechanisms of the CXCL13-CXCR5 axis under normal conditions, with special focus on its association with diseases. For certain refractory diseases, we emphasize the diagnostic and therapeutic role of CXCL13-CXCR5 axis.

The Relationship between Cancer and Paraoxonase 1

Extensive research has been carried out to understand and elucidate the mechanisms of paraoxonase 1 (PON1) in the development of diseases including cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. This review focuses on the relationship between PON1 and cancer. The data suggest that PON1, oxidative stress, chronic inflammation, and cancer are closely linked. Certainly, the gene expression of PON1 will remain challenging to study. Therefore, targeting PON1, redox-sensitive pathways, and transcription factors promise prevention and therapy in the development of several diseases, including cancer.

HM-chromanone attenuates TNF-α-mediated inflammation and insulin resistance by controlling JNK activation and NF-κB pathway in 3T3-L1 adipocytes

Obesity is a major public health problem worldwide and causes inflammation and insulin resistance in adipose tissue. We investigated the ability of (E)-5-hydroxy-7-methoxy-3-(2'-hydroxybenzyl)-4-chromanone (HM-chromanone) isolated from Portulaca oleracea to attenuate the activation of inflammatory cytokines and signaling pathways associated with tumor necrosis factor (TNF)-α-mediated inflammation and insulin resistance in 3T3-L1 adipocytes. TNF-α triggers the release of inflammatory cytokines and activation of the mitogen-activated protein kinase and nuclear factor (NF)-κB signaling pathways. In this study, HM-chromanone inhibited the production of inflammatory cytokines and chemokines [TNF-α, interleukin (IL)-6, IL-1β, and monocyte chemoattractant protein 1] involved in inflammation and insulin resistance. Furthermore, TNF-α treatment increased c-Jun-NH2 terminal kinase (JNK) phosphorylation, whereas HM-chromanone significantly decreased JNK phosphorylation in a dose-dependent manner. TNF-α treatment increased the activation of inhibitor kappa B (IκB) kinase (IKK), IκBα, and NF-κBp65 compared with that of the control. However, HM-chromanone significantly blocked IKK, IκBα, and NF-κBp65 activation. Upon adipocyte stimulation with TNF-α, phosphorylated insulin receptor substrate (pIRS)-1 serine 307 levels increased and pIRS-1 tyrosine 612 levels decreased compared with those of the control. Upon treatment with HM-chromanone, serine 307 phosphorylation of IRS-1 was inhibited and tyrosine 612 phosphorylation of IRS-1 was increased. Thus, HM-chromanone improved TNF-α-mediated inflammation and insulin resistance by regulating JNK activation and the NF-κB pathway, thereby reducing inflammatory cytokine secretion and inhibiting serine phosphorylation of IRS-1 in the insulin signaling pathway. These results suggest the potential of HM-chromanone to improve inflammatory conditions and insulin resistance in adipocytes.

IKKα plays a major role in canonical NF-kB signalling in colorectal cells

Inhibitor of kappa B (IκB) kinase β (IKKβ) has long been viewed as the dominant IKK in the canonical nuclear factor-κB (NF-κB) signalling pathway, with IKKα being more important in non-canonical NF-κB activation. Here we have investigated the role of IKKα and IKKβ in canonical NF-κB activation in colorectal cells using CRISPR–Cas9 knock-out cell lines, siRNA and selective IKKβ inhibitors. IKKα and IKKβ were redundant for IκBα phosphorylation and turnover since loss of IKKα or IKKβ alone had little (SW620 cells) or no (HCT116 cells) effect. However, in HCT116 cells IKKα was the dominant IKK required for basal phosphorylation of p65 at S536, stimulated phosphorylation of p65 at S468, nuclear translocation of p65 and the NF-κB-dependent transcriptional response to both TNFα and IL-1α. In these cells, IKKβ was far less efficient at compensating for the loss of IKKα than IKKα was able to compensate for the loss of IKKβ. This was confirmed when siRNA was used to knock-down the non-targeted kinase in single KO cells. Critically, the selective IKKβ inhibitor BIX02514 confirmed these observations in WT cells and similar results were seen in SW620 cells. Notably, whilst IKKα loss strongly inhibited TNFα-dependent p65 nuclear translocation, IKKα and IKKβ contributed equally to c-Rel nuclear translocation indicating that different NF-κB subunits exhibit different dependencies on these IKKs. These results demonstrate a major role for IKKα in canonical NF-κB signalling in colorectal cells and may be relevant to efforts to design IKK inhibitors, which have focused largely on IKKβ to date.

Origin of the Functional Distinctiveness of NF-κB/p52

The transcription regulators of the NF-κB family have emerged as a critical factor affecting the function of various adult tissues. The NF-κB family transcription factors are homo- and heterodimers made up of five monomers (p50, p52, RelA, cRel and RelB). The family is distinguished by sequence homology in their DNA binding and dimerization domains, which enables them to bind similar DNA response elements and participate in similar biological programs through transcriptional activation and repression of hundreds of genes. Even though the family members are closely related in terms of sequence and function, they all display distinct activities. In this review, we discuss the sequence characteristics, protein and DNA interactions, and pathogenic involvement of one member of family, NF-κB/p52, relative to that of other members. We pinpoint the small sequence variations within the conserved region that are mostly responsible for its distinct functional properties.

CXCL13 in Cancer and Other Diseases: Biological Functions, Clinical Significance, and Therapeutic Opportunities

The development of cancer is a multistep and complex process involving interactions between tumor cells and the tumor microenvironment (TME). C-X-C chemokine ligand 13 (CXCL13) and its receptor, CXCR5, make crucial contributions to this process by triggering intracellular signaling cascades in malignant cells and modulating the sophisticated TME in an autocrine or paracrine fashion. The CXCL13/CXCR5 axis has a dominant role in B cell recruitment and tertiary lymphoid structure formation, which activate immune responses against some tumors. In most cancer types, the CXCL13/CXCR5 axis mediates pro-neoplastic immune reactions by recruiting suppressive immune cells into tumor tissues. Tobacco smoke and haze (smohaze) and the carcinogen benzo(a)pyrene induce the secretion of CXCL13 by lung epithelial cells, which contributes to environmental lung carcinogenesis. Interestingly, the knockout of CXCL13 inhibits benzo(a)pyrene-induced lung cancer and azoxymethane/dextran sodium sulfate-induced colorectal cancer in mice. Thus, a better understanding of the context-dependent functions of the CXCL13/CXCR5 axis in tumor tissue and the TME is required to design an efficient immune-based therapy. In this review, we summarize the molecular events and TME alterations caused by CXCL13/CXCR5 and briefly discuss the potentials of agents targeting this axis in different malignant tumors.

The role of the ubiquitin-proteasome pathway in skin cancer development: 26S proteasome-activated NF-κB signal transduction

The Ubiquitin-Proteasome System plays a central role in signal transduction associated with stress, in the skin in particular by the control of NF-κB pathways. Under normal conditions, the inhibitory protein IκB is phosphorylated by kinases, then ubiquitinated and ends up at the proteasome to be degraded. The present short review discusses recent progress in the inhibition of NF-κB activation by proteasome inhibitors prevents the degradation of protein IκB, which accumulates in the cytosol, and there by the activation of NF-κB. Moreover, would not only limit the expression of adhesion molecules and cytokines involved in metastatic processes, but also increase the sensitivity of cancer cells to apoptosis. Considering this fact, the activity of NF-κB is regulated by the phosphorylation and proteasome-dependent degradation of its inhibitor Iκb. In this scenario, the use of a proteasome inhibitor might be an effective strategy in the treatment of skin cancer with constitutive activation of NF-κB.

Challenges with Methods for Detecting and Studying the Transcription Factor Nuclear Factor Kappa B (NF-κB) in the Central Nervous System

The transcription factor nuclear factor kappa B (NF-κB) is highly expressed in almost all types of cells. NF-κB is involved in many complex biological processes, in particular in immunity. The activation of the NF-κB signaling pathways is also associated with cancer, diabetes, neurological disorders and even memory. Hence, NF-κB is a central factor for understanding not only fundamental biological presence but also pathogenesis, and has been the subject of intense study in these contexts. Under healthy physiological conditions, the NF-κB pathway promotes synapse growth and synaptic plasticity in neurons, while in glia, NF-κB signaling can promote pro-inflammatory responses to injury. In addition, NF-κB promotes the maintenance and maturation of B cells regulating gene expression in a majority of diverse signaling pathways. Given this, the protein plays a predominant role in activating the mammalian immune system, where NF-κB-regulated gene expression targets processes of inflammation and host defense. Thus, an understanding of the methodological issues around its detection for localization, quantification, and mechanistic insights should have a broad interest across the molecular neuroscience community. In this review, we summarize the available methods for the proper detection and analysis of NF-κB among various brain tissues, cell types, and subcellular compartments, using both qualitative and quantitative methods. We also summarize the flexibility and performance of these experimental methods for the detection of the protein, accurate quantification in different samples, and the experimental challenges in this regard, as well as suggestions to overcome common challenges.

Mechanism of Gene-Environment Interactions Driving Glial Activation in Parkinson's Diseases

PURPOSE OF REVIEW

Parkinson's disease (PD) is the most prevalent motor disorder and is characterized by loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) region of the brain. Though the pathology of PD is well established, the cause of this neuronal loss is not well understood. Approximately 90% of PD cases are sporadic, and the environment plays a significant role in disease pathogenesis. The etiology of PD is highly complex, with neuroinflammation being one of the most critical factors implicated in PD. However, the signaling mechanisms underlying neuroinflammation and its interaction with environmental factors are unclear.

RECENT FINDINGS

Astroglia and microglia are the two principal cells that play an essential role in maintaining neuronal health in many ways, including through immunological means. Exposure to environmental stressors from various sources affects these glial cells leading to chronic and sustained inflammation. Recent epidemiological studies have identified an interaction among environmental factors and glial genes in Parkinson's disease. Mechanistic studies have shown that exposure to pesticides like rotenone and paraquat, neurotoxic metals like manganese and lead, and even diesel exhaust fumes induce glial activation by regulating various key inflammatory pathways, including the inflammasomes, NOX pathways, and others. This review aims to discuss the recent advances in understanding the mechanism of glial induction in response to environmental stressors and discuss the potential role of gene-environment interaction in driving glial activation.

Therapeutic perspective of thiosemicarbazones derivatives in inflammatory pathologies: A summary of in vitro/in vivo studies

Following induction of inflammation, the nuclear factor kappa B (NF-κB) in activated macrophages induces the transcription of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and cyclooxygenase (COX), an inflammatory enzyme implicated in the synthesis of prostaglandins (PGs). The latter are involved in the transition and the maintenance of chronic inflammation underling various chronic disorders that require treatment. Concerning this, many anti-inflammatory drugs are available to treat the inflammatory disorders, but their therapeutic use is associated with a variety of side effects. Therefore, the discovery of new safer and potential anti-inflammatory drugs is necessary. In this regard, thiosemicarbazones (TSC) compounds and their metals complexes attracted high interest due to their wide range of biological activities, interestingly, the anti-inflammatory activity. They are formed by the action of thiosemicarbazide on an aldehyde or ketone, and contain a sulfur atom in place of the oxygen atom. Their ability to form a stable complex with transition metal is known to enhances the biological activity and reduces the side effects of the parent compound. Thus, this review article describes the inflammatory response mediated by NF-κB-COX-PGs and summarizes the anti-inflammatory activity of different thiosemicarbazones derivatives synthesized in research area.

CXCL13 promotes intestinal tumorigenesis through the activation of epithelial AKT signaling

The excessive release of proinflammatory chemokines promotes cell proliferation and tumor growth in colorectal cancer. However, their regulatory functions and molecular pathogenesis have not been well elucidated. Here, we observed the upregulation of chemokine (C-X-C motif) ligand 13 (CXCL13) in human colorectal cancers and mouse intestinal tumors. Both CXCL13 deficiency and blockade of CXCL13 signaling ameliorated disease progression. CXCL13 promoted intestinal tumorigenesis through the activation of the AKT signaling pathway in a C-X-C chemokine receptor type 5 (CXCR5)-dependent manner. Intestinal microbiota translocation drove CXCL13 production in dendritic cells through the activation of NF-κB signaling. Inhibition of microbiota translocation decreased CXCL13 production and ameliorated intestinal tumorigenesis. Together, the results of this study identify a role for the CXCL13-CXCR5 axis is involved in the crosstalk between chemokines and cell growth during the development of intestinal tumorigenesis, which also provides a therapeutic strategy for targeting CXCL13/CXCR5 in the future clinical treatment of intestinal tumors.

Mutual regulation of metabolic processes and proinflammatory NF-κB signaling

The nuclear factor kappa B (NF-κB) signaling system, a key regulator of immunologic processes, also affects a plethora of metabolic changes associated with inflammation and the immune response. NF-κB-regulating signaling cascades, in concert with NF-κB-mediated transcriptional events, control the metabolism at several levels. NF-κB modulates apical components of metabolic processes including metabolic hormones such as insulin and glucagon, the cellular master switches 5' AMP-activated protein kinase and mTOR, and also numerous metabolic enzymes and their respective regulators. Vice versa, metabolic enzymes and their products also exert multilevel control of NF-κB activity, thereby creating a highly connected regulatory network. These insights have resulted in the identification of the noncanonical IκB kinase kinases IκB kinase ɛ and TBK1, which are upregulated by overnutrition, and may therefore be suitable potential therapeutic targets for metabolic syndromes. An inhibitor interfering with the activity of both kinases reduces obesity-related metabolic dysfunctions in mouse models and the encouraging results from a recent clinical trial indicate that targeting these NF-κB pathway components improves glucose homeostasis in a subset of patients with type 2 diabetes.

Nuclear Factor Kappa B Signaling Complexes in Acute Inflammation

Significance: Nuclear factor kappa B (NF-κB) is a master regulator of the inflammatory response and represents a key regulatory node in the complex inflammatory signaling network. In addition, selective NF-κB transcriptional activity on specific target genes occurs through the control of redox-sensitive NF-κB interactions. Recent Advances: The selective NF-κB response is mediated by redox-modulated NF-κB complexes with ribosomal protein S3 (RPS3), Pirin (PIR). cAMP response element-binding (CREB)-binding protein (CBP)/p300, peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), activator protein-1 (AP-1), signal transducer and activator of transcription 3 (STAT3), early growth response protein 1 (EGR-1), and SP-1. NF-κB is cooperatively coactivated with AP-1, STAT3, EGR-1, and SP-1 during the inflammatory process, whereas NF-κB complexes with CBP/p300 and PGC-1α regulate the expression of antioxidant genes. PGC-1α may act as selective repressor of phospho-p65 toward interleukin-6 (IL-6) in acute inflammation. p65 and nuclear factor erythroid 2-related factor 2 (NRF2) compete for binding to coactivator CBP/p300 playing opposite roles in the regulation of inflammatory genes. S-nitrosylation or tyrosine nitration favors the recruitment of specific NF-κB subunits to κB sites. Critical Issues: NF-κB is a redox-sensitive transcription factor that forms specific signaling complexes to regulate selectively the expression of target genes in acute inflammation. Protein-protein interactions with coregulatory proteins, other transcription factors, and chromatin-remodeling proteins provide transcriptional specificity to NF-κB. Furthermore, different NF-κB subunits may form distinct redox-sensitive homo- and heterodimers with distinct affinities for κB sites. Future Directions: Further research is required to elucidate the whole NF-κB interactome to fully characterize the complex NF-κB signaling network in redox signaling, inflammation, and cancer.

Pharmacological Activation of Non-canonical NF-κB Signaling Activates Latent HIV-1 Reservoirs In Vivo

"Shock and kill" strategies focus on purging the latent HIV-1 reservoir by treating infected individuals with therapeutics that activate the latent virus and subsequently eliminating infected cells. We have previously reported that induction of non-canonical nuclear factor κB (NF-κB) signaling through a class of small-molecule antagonists known as Smac mimetics can reverse HIV-1 latency. Here, we describe the development of Ciapavir (SBI-0953294), a molecule specifically optimized for HIV-1 latency reversal that was found to be more efficacious as a latency-reversing agent than other Smac mimetics under clinical development for cancer. Critically, this molecule induced activation of HIV-1 reservoirs in vivo in a bone marrow, liver, thymus (BLT) humanized mouse model without mediating systemic T cell activation. This study provides proof of concept for the in vivo efficacy and safety of Ciapavir and indicates that Smac mimetics can constitute a critical component of a safe and efficacious treatment strategy to eliminate the latent HIV-1 reservoir.

Targeting codon 158 p53-mutant cancers via the induction of p53 acetylation

Gain of function (GOF) DNA binding domain (DBD) mutations of TP53 upregulate chromatin regulatory genes that promote genome-wide histone methylation and acetylation. Here, we therapeutically exploit the oncogenic GOF mechanisms of p53 codon 158 (Arg¹⁵⁸) mutation, a DBD mutant found to be prevalent in lung carcinomas. Using high throughput compound screening and combination analyses, we uncover that acetylating mutp53^R158G could render cancers susceptible to cisplatin-induced DNA stress. Acetylation of mutp53^R158G alters DNA binding motifs and upregulates TRAIP, a RING domain-containing E3 ubiquitin ligase which dephosphorylates IĸB and impedes nuclear translocation of RelA (p65), thus repressing oncogenic nuclear factor kappa-B (NF-ĸB) signaling and inducing apoptosis. Given that this mechanism of cytotoxic vulnerability appears inapt in p53 wild-type (WT) or other hotspot GOF mutp53 cells, our work provides a therapeutic opportunity specific to Arg¹⁵⁸-mutp53 tumors utilizing a regimen consisting of DNA-damaging agents and mutp53 acetylators, which is currently being pursued clinically.

Codon 158 gain-of-function mutant p53 (158-mutp53) promotes tumourigenesis in lung cancer. Here, the authors show that 158-mutp53 render cancers sensitive to cisplatin and p53 acetylation agents through a mechanism where acetylated mutant p53 upregulates TRAIP and inhibits NF-ĸB signaling.

Persistent Breeding-Induced Endometritis in Mares - a Multifaceted Challenge: From Clinical Aspects to Immunopathogenesis and Pathobiology

Post-breeding endometritis (i.e., inflammation/infection of the endometrium), is a physiological reaction taking place in the endometrium of mares within 48 hours post-breeding, aimed to clear seminal plasma, excess sperm, microorganisms, and debris from the uterine lumen in preparation for the arrival of an embryo. Mares are classified as susceptible or resistant to persistent breeding-induced endometritis (PBIE) based on their ability to clear this inflammation/infection by 48 hours post-breeding. Mares susceptible to PBIE, or those with difficulty clearing infection/inflammation, have a deficient immune response and compromised physical mechanisms of defense against infection. Molecular pathways of the innate immune response known to be involved in PBIE are discussed herein. The role of the adaptive uterine immune response on PBIE remains to be elucidated in horses. Advances in the pathobiology of microbes involved in PBIE are also revised here. Traditional and non-traditional therapeutic modalities for endometritis are contrasted and described in the context of clinical and molecular aspects. In recent years, the lack of efficacy of traditional therapeutic modalities, alongside the ever-increasing incidence of antibiotic-resistant microorganisms, has enforced the development of non-traditional therapies. Novel biological products capable of modulating the endometrial inflammatory response are also discussed here as part of the non-traditional therapies for endometritis.

Human umbilical cord mesenchymal stem cell exosomes alleviate sepsis-associated acute kidney injury via regulating microRNA-146b expression

Human umbilical cord mesenchymal stem cell-derived exosomes (HucMSC-Ex) are a promising tool for the repair of acute kidney injury (AKI) caused by cisplatin and ischemia/reperfusion. However, the roles of hucMSC-Ex in sepsis-associated AKI repair and its mechanism are largely unknown. Hence, we constructed a sepsis model through cecal ligation and puncture (CLP), testing the benefits of hucMSC-Ex in the sepsis in terms of survival rate, serum renal markers levels, morphological changes and apoptosis. Immunohistochemistry staining and immunofluorescence assay were used to investigate the role of NF-κB activity in the repair of sepsis-associated AKI with hucMSC-Ex. HK-2 cells were transfected with microRNA-146b (miR-146b) mimics and inhibitors, respectively, and the regulatory effect of miR-146b on NF-κB activity was studied. We found that hucMSC-Ex treatment significantly decreased the serum creatinine (Cr) and blood urea nitrogen (BUN) levels, ameliorated the morphological damage and inhibited renal tubular cells apoptosis. More importantly, the survival rate at 72 h was 28% in CLP group and 45% in hucMSC-Ex group, respectively. Treatment with hucMSC-Ex improved survival in mice with sepsis. These effects of hucMSC-Ex were mediated by the inhibition of NF-κB activity and the lessening of pro-inflammatory response. Furthermore, hucMSC-Ex significantly increased miR-146b expression in kidney tissues. Conversely, interleukin (IL)-1 receptor-associated kinase (IRAK1) level, which is the target gene of miR-146b, clearly decreased in hucMSC-Ex group. In brief, this study showed that treatment with hucMSC-Ex decreased IRAK1 expression through the up-regulation of miR-146b level, led to the inhibition of NF-κB activity, and eventually alleviated sepsis-associated AKI and improved survival in mice with sepsis. HucMSC-Ex may be a novel therapeutic agent for the reduction of sepsis-associated AKI.

Genome reading by the NF-κB transcription factors

The NF-κB family of dimeric transcription factors regulates transcription by selectively binding to DNA response elements present within promoters or enhancers of target genes. The DNA response elements, collectively known as κB sites or κB DNA, share the consensus 5'-GGGRNNNYCC-3' (where R, Y and N are purine, pyrimidine and any nucleotide base, respectively). In addition, several DNA sequences that deviate significantly from the consensus have been shown to accommodate binding by NF-κB dimers. X-ray crystal structures of NF-κB in complex with diverse κB DNA have helped elucidate the chemical principles that underlie target selection in vitro. However, NF-κB dimers encounter additional impediments to selective DNA binding in vivo. Work carried out during the past decades has identified some of the barriers to sequence selective DNA target binding within the context of chromatin and suggests possible mechanisms by which NF-κB might overcome these obstacles. In this review, we first highlight structural features of NF-κB:DNA complexes and how distinctive features of NF-κB proteins and DNA sequences contribute to specific complex formation. We then discuss how native NF-κB dimers identify DNA binding targets in the nucleus with support from additional factors and how post-translational modifications enable NF-κB to selectively bind κB sites in vivo.

The Human Papillomavirus (HPV) E1 protein regulates the expression of cellular genes involved in immune response

The Human Papillomavirus (HPV) E1 protein is the only viral protein with enzymatic activity. The main known function of this protein is the regulation of the viral DNA replication. Nevertheless, it has been demonstrated that the ablation of HPV18 E1 mRNA in HeLa cells promotes a deregulation of several genes, particularly those involved in host defense mechanisms against viral infections; however, the specific contribution of E1 protein in HPV-independent context has not been studied. The aim of this work was to determine the effect of the HPV E1 protein in the regulation of cellular gene expression profiles evaluated through RNA-seq. We found that E1 proteins from HPV16 and 18 induced an overexpression of different set of genes associated with proliferation and differentiation processes, as well as downregulation of immune response genes, including IFNβ1 and IFNλ1 and Interferon-stimulated gene (ISG), which are important components involved in the antiviral immune response. Together, our results indicate that HR-(High-Risk) and LR-(Low-Risk) HPV E1 proteins play an important role in inhibiting the anti-viral immune response.

MAP3K kinases and kidney injury

Mitogen-activated protein kinases (MAP kinases) are functionally connected kinases that regulate key cellular process involved in kidney disease such as all survival, death, differentiation and proliferation. The typical MAP kinase module is composed by a cascade of three kinases: a MAP kinase kinase kinase (MAP3K) that phosphorylates and activates a MAP kinase kinase (MAP2K) which phosphorylates a MAP kinase (MAPK). While the role of MAPKs such as ERK, p38 and JNK has been well characterized in experimental kidney injury, much less is known about the apical kinases in the cascade, the MAP3Ks. There are 24 characterized MAP3K (MAP3K1 to MAP3K21 plus RAF1, BRAF and ARAF). We now review current knowledge on the involvement of MAP3K in non-malignant kidney disease and the therapeutic tools available. There is in vivo interventional evidence clearly supporting a role for MAP3K5 (ASK1) and MAP3K14 (NIK) in the pathogenesis of experimental kidney disease. Indeed, the ASK1 inhibitor Selonsertib has undergone clinical trials for diabetic kidney disease. Additionally, although MAP3K7 (MEKK7, TAK1) is required for kidney development, acutely targeting MAP3K7 protected from acute and chronic kidney injury; and targeting MAP3K8 (TPL2/Cot) protected from acute kidney injury. By contrast MAP3K15 (ASK3) may protect from hypertension and BRAF inhibitors in clinical use may induced acute kidney injury and nephrotic syndrome. Given their role as upstream regulators of intracellular signaling, MAP3K are potential therapeutic targets in kidney injury, as demonstrated for some of them. However, the role of most MAP3K in kidney disease remains unexplored.

The cardiovascular protective effects of rooibos (Aspalathus linearis) extract on diesel exhaust particles induced inflammation and oxidative stress involve NF-κB- and Nrf2-dependent pathways modulation

Studies have shown that diesel exhaust particles (DEP) induced oxidative stress and inflammation. This present study examined the molecular effects of aqueous rooibos extract (RE) on the cardiovascular toxic effect of methanol extract of DEP in exposed Wistar rats. The results showed that DEP caused significant (p < 0.001) increase in MDA and CDs levels in the aorta and heart but this increase was significantly (p < 0.001) attenuated by rooibos extract. DEP induced IL-8, TNFα, IL-1β and decreased IL-10 gene expressions, all of which were reversed in the presence of rooibos extract. The expression of NF-κB, and IκKB genes were also significantly (p < 0.001) induced by DEP in both tissues, but pre-treatment with RE attenuated these effects. In contrast, DEP repressed IκB mRNA level, which was significantly (p < 0.001) reversed by rooibos extract pre-treatment. In addition, pre-treatment with rooibos extract attenuated the increased Nrf2 and HO-1 mRNA levels caused by DEP. This indicates the potential of rooibos extract to protect against DEP-induced cardiovascular toxicity.

NIK-IKK complex interaction controls NF-κB-dependent inflammatory activation of endothelium in response to LTβR ligation

NF-κB-inducing kinase (NIK; also known as MAP3K14) is a central regulator of non-canonical NF-κB signaling in response to stimulation of TNF receptor superfamily members, such as the lymphotoxin-β receptor (LTβR), and is implicated in pathological angiogenesis associated with chronic inflammation and cancer. Here, we identify a previously unrecognized role of the LTβR-NIK axis during inflammatory activation of human endothelial cells (ECs). Engagement of LTβR-triggered canonical and non-canonical NF-κB signaling promoted expression of inflammatory mediators and adhesion molecules, and increased immune cell adhesion to ECs. Sustained LTβR-induced inflammatory activation of ECs was NIK dependent, but independent of p100, indicating that the non-canonical arm of NF-κB is not involved. Instead, prolonged activation of canonical NF-κB signaling, through the interaction of NIK with IκB kinase α and β (also known as CHUK and IKBKB, respectively), was required for the inflammatory response. Endothelial inflammatory activation induced by synovial fluid from rheumatoid arthritis patients was significantly reduced by NIK knockdown, suggesting that NIK-mediated alternative activation of canonical NF-κB signaling is a key driver of pathological inflammatory activation of ECs. Targeting NIK could thus provide a novel approach for treating chronic inflammatory diseases.

Below the surface: The inner lives of TLR4 and TLR9

TLRs are a class of pattern recognition receptors (PRRs) that detect invading microbes by recognizing pathogen-associated molecular patterns (PAMPs). Upon PAMP engagement, TLRs activate a signaling cascade that leads to the production of inflammatory mediators. The localization of TLRs, either on the plasma membrane or in the endolysosomal compartment, has been considered to be a fundamental aspect to determine to which ligands the receptors bind, and which transduction pathways are induced. However, new observations have challenged this view by identifying complex trafficking events that occur upon TLR-ligand binding. These findings have highlighted the central role that endocytosis and receptor trafficking play in the regulation of the innate immune response. Here, we review the TLR4 and TLR9 transduction pathways and the importance of their different subcellular localization during the inflammatory response. Finally, we discuss the implications of TLR9 subcellular localization in autoimmunity.

Essential Role of Canonical NF-κB Activity in the Development of Stromal Cell Subsets in Secondary Lymphoid Organs

Organized tissue structure in the secondary lymphoid organs (SLOs) tightly depends on the development of fibroblastic stromal cells (FSCs) of mesenchymal origin; however, the mechanisms of this relationship are poorly understood. In this study, we specifically inactivated the canonical NF-κB pathway in FSCs in vivo by conditionally inducing IκBα mutant in a Ccl19-IκBSR mouse system in which NF-κB activity is likely to be suppressed in fetal FSC progenitors. Given that NF-κB activation in fetal FSCs is essential for SLO development, the animals were expected to lack SLOs. However, all SLOs were preserved in Ccl19-IκBSR mice. Instead, the T cell area was severely disturbed by the lack of CCL21-expressing FSCs, whereas the follicles and associated FSC networks were formed. Fate mapping revealed that IκBSR-expressing cells constituted only a small fraction of stromal compartment outside the follicles. Taken together, our findings indicate an essential role of the canonical NF-κB pathway activity in the development of three FSC subsets common to SLOs and suggest transient or stochastic CCL19 expression in FSC progenitors and a compensatory differentiation program of follicular FSCs.

Targeting IKKβ in Cancer: Challenges and Opportunities for the Therapeutic Utilisation of IKKβ Inhibitors

Deregulated NF-κB signalling is implicated in the pathogenesis of numerous human inflammatory disorders and malignancies. Consequently, the NF-κB pathway has attracted attention as an attractive therapeutic target for drug discovery. As the primary, druggable mediator of canonical NF-κB signalling the IKKβ protein kinase has been the historical focus of drug development pipelines. Thousands of compounds with activity against IKKβ have been characterised, with many demonstrating promising efficacy in pre-clinical models of cancer and inflammatory disease. However, severe on-target toxicities and other safety concerns associated with systemic IKKβ inhibition have thus far prevented the clinical approval of any IKKβ inhibitors. This review will discuss the potential reasons for the lack of clinical success of IKKβ inhibitors to date, the challenges associated with their therapeutic use, realistic opportunities for their future utilisation, and the alternative strategies to inhibit NF-κB signalling that may overcome some of the limitations associated with IKKβ inhibition.

The non-canonical NF-κB pathway promotes NPC2 expression and regulates intracellular cholesterol trafficking

Niemann-Pick type C2 (NPC2) is a lysosome luminal protein that functions in concert with NPC1 to mediate egress of low-density lipoprotein-derived cholesterol from lysosome. The nuclear factor kappa B subunit 2 (NF-κB2) protein is a component of NF-κB transcription factor complex critically implicated in immune and inflammatory responses. Here, we report that NF-κB2 regulates intracellular cholesterol transport by controlling NPC2 expression. RNAi-mediated disruption of NF-κB2, as well as other signaling members of the non-canonical NF-κB pathway, caused intracellular cholesterol accumulation. Blockage of the non-canonical NF-κB pathway suppressed NPC2 expression, whereas Lymphotoxin β receptor (LTβR) activation or Baff receptor (BaffR) stimulation up-regulated the mRNA abundance and protein level of NPC2. Further, NF-κB2 activated NPC2 transcription through direct binding to its promoter region. We also observed cholesterol accumulation in NF-κB2-deficient zebrafish embryo and NF-κB2 mutant mice. Collectively, these data identify a regulatory role for the non-canonical NF-κB pathway in intracellular cholesterol trafficking and suggest a link between cholesterol transport and immune system.

HZ08 suppresses RelB-activated MnSOD expression and enhances Radiosensitivity of prostate Cancer cells

Background

The development of radioresistance is one of main causes for therapeutic failure of prostate cancer (PCa). The present study aims to investigate the function and the related mechanism by which HZ08 sensitizes radiotherapeutic efficiency to treat aggressive PCa cells.

Methods

PCa cells were pretreated with HZ08 (6,7-dimethoxy-1-(3,4-dimethoxy) benzyl-2-(N-n-octyl-N′-cyano) guanyl-1,2,3,4-tetrahydroisoquinoline) and followed by ionizing radiation (IR) treatment. Cytotoxicity in the treated cells was analyzed to assess the radiosensitization capacity of HZ08 by flow cytometry, MTT and colony survival assays. The cellular levels of reactive oxygen species (ROS) and oxygen consumption rates (OCR) were measured using specific ROS detection probes and a Seahorse XF96 Analyzer, respectively. RelB binding to the NF-κB intronic enhancer region of the human SOD2 gene was determined using a ChIP assay. The levels of phosphorylation of PI3K, Akt and IKKα were quantified and further confirmed using a PI3K inhibitor. Finally, the synergistic effect of HZ08 on radiosensitization of PCa cells was validated using a mouse xenograft tumor model.

Results

HZ08 enhanced radiosensitivity of PCa cells through increasing ROS and declining mitochondrial respiration due to suppression of mitochondrial antioxidant enzyme MnSOD. Mechanistically, HZ08 appeared to inhibit PI3K/Akt/IKKα signaling axis, resulting in transcriptional repression of MnSOD expression by preventing RelB nuclear translocation.

Conclusions

HZ08 can serve as a useful radiosensitizing agent to improve radiotherapy for treating aggressive PCa cells with high level of constitutive RelB. The present study suggests a promising approach for enhancing radiotherapeutic efficiency to treat advanced PCa by inhibiting antioxidant defense function.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0849-5) contains supplementary material, which is available to authorized users.

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.

The NF-κB Activating Pathways in Multiple Myeloma

Multiple myeloma(MM), an incurable plasma cell cancer, represents the second most prevalent hematological malignancy. Deregulated activity of the nuclear factor kappaB (NF-κB) family of transcription factors has been implicated in the pathogenesis of multiple myeloma. Tumor microenvironment-derived cytokines and cancer-associated genetic mutations signal through the canonical as well as the non-canonical arms to activate the NF-κB system in myeloma cells. In fact, frequent engagement of both the NF-κB pathways constitutes a distinguishing characteristic of myeloma. In turn, NF-κB signaling promotes proliferation, survival and drug-resistance of myeloma cells. In this review article, we catalog NF-κB activating genetic mutations and microenvironmental cues associated with multiple myeloma. We then describe how the individual canonical and non-canonical pathways transduce signals and contribute towards NF-κB -driven gene-expressions in healthy and malignant cells. Furthermore, we discuss signaling crosstalk between concomitantly triggered NF-κB pathways, and its plausible implication for anomalous NF-κB activation and NF-κB driven pro-survival gene-expressions in multiple myeloma. Finally, we propose that mechanistic understanding of NF-κB deregulations may provide for improved therapeutic and prognostic tools in multiple myeloma.

Inhibition of nuclear factor kappa B pathway protects myocardial ischemia/reperfusion injury in rats under treatment with abnormal savda munziq

OBJECTIVE

Uighur medicine Fufang Munziq granule (Munziq) [corrected] shows cardioprotective effect in myocardial ischemia/reperfusion injury (IRI) in animal models, but the molecular mechanism of this effect is not clear. The present study investigates the regulation of nuclear factor kappa B (NF-kappa B) pathway by Fufang Munziq granule (Munziq) in IRI rat models.

METHODS

Male Sprague-Dawley rats were divided into three groups: the NF-κB gene knockout group (n = 5); the NF-κB transgenic group (n = 8); and the control group (n = 5). All rats were treated with Fufang Munziq granule (Munziq) [corrected] for 21 days before underwent IRI surgical procedure. Blood and tissue samples were collected for the RT-PCR, ELISA, western blot and other examination.

RESULTS

Expression of NF-κB p65mRNA and protein were down-regulated in the NF-κB knockout rats but up-regulated in the transgenic rats comparing with the controls (P<0.05). The upstream NF-κB kinase expressions, the downstream inflammatory cytokines, and the myocardial injury markers were all changed in accordance with the NF-κB gene modification (all P values <0.05). AMSq treatment relieved IRI in the NF-κB knockout rats.

CONCLUSION

Inhibition on NF-κB signaling pathway may alleviate IRI in rats under Fufang Munziq granule (Munziq) [corrected] treatment.

A TNF-p100 pathway subverts noncanonical NF-κB signaling in inflamed secondary lymphoid organs

Lymphotoxin-beta receptor (LTβR) present on stromal cells engages the noncanonical NF-κB pathway to mediate RelB-dependent expressions of homeostatic chemokines, which direct steady-state ingress of naïve lymphocytes to secondary lymphoid organs (SLOs). In this pathway, NIK promotes partial proteolysis of p100 into p52 that induces nuclear translocation of the RelB NF-κB heterodimers. Microbial infections often deplete homeostatic chemokines; it is thought that infection-inflicted destruction of stromal cells results in the downregulation of these chemokines. Whether inflammation per se also regulates these processes remains unclear. We show that TNF accumulated upon non-infectious immunization of mice similarly downregulates the expressions of these chemokines and consequently diminishes the ingress of naïve lymphocytes in inflamed SLOs. Mechanistically, TNF inactivated NIK in LTβR-stimulated cells and induced the synthesis of Nfkb2 mRNA encoding p100; these together potently accumulated unprocessed p100, which attenuated the RelB activity as inhibitory IκBδ. Finally, a lack of p100 alleviated these TNF-mediated inhibitions in inflamed SLOs of immunized Nfkb2-/- mice. In sum, we reveal that an inhibitory TNF-p100 pathway modulates the adaptive compartment during immune responses.

The role of Nuclear Factor-kappa B signaling in human cervical cancer

Background The Nuclear Factor kappaB (NF-kB) family consists of transcription factors that play a complex and essential role in the regulation of immune responses and inflammation. NF-kB has recently generated considerable interest as it has been implicated in human cancer initiation, progression and resistance to treatment. In the present comprehensive review the different aspects of NF-kB signaling in the carcinogenesis of cancer of the uterine cervix are discussed. NF-kB functions as part of a network, which determines the pattern of its effects on the expression of several other genes (such as crosstalks with reactive oxygen species, p53, STAT3 and miRNAS) and thus its function. Activation of NF-kB triggered by a HPV infection is playing an important role in the innate and adaptive immune response of the host. The virus induces down regulation of NF-kB to liquidate the inhibitory activity for its replication triggered by the immune system leading a status of persistant HPV infection. During the progression to high grade intraepithelial neoplasia and cervical cancer NF-KB becomes constitutionally activated again. Mutations in NF-kB genes are rare in solid tumors but mutations of upstream signaling molecules such as RAS, EGFR, PGF, HER2 have been implicated in elevated NF-kB signaling. NF-kB can stimulate transcription of proliferation regulating genes (eg. cyclin D1 and c-myc), genes involved in metastasis, VEGF dependent angiogenesis and cell immortality by telomerase. NF-kB activation can also induce the expression of activation-induced cytodine deaminase (AID) and the APOBEC proteins, providing a mechanistic link between the NF-kB pathway and mutagenic characteristic of cervical cancer. Inhibition of NF-kB has the potential to be used to reverse resistance to radiotherapy and systemic anti-cancer medication, but currently no clinicaly active NF-kB targeting strategies are available.