Crosstalk via the NF-kappaB signaling system

Podophyllotoxin via SIRT1/PPAR /NF-κB axis induced cardiac injury in rats based on the toxicological evidence chain (TEC) concept

BACKGROUND

The study of cardiotoxicity of drugs has become an important part of clinical safety evaluation of drugs. It is commonly known that podophyllotoxin (PPT) and its many derivatives and congeners are broad-spectrum pharmacologically active substances. Clinical cardiotoxicity of PPT and its derivatives has been raised, basic research on the mechanism of cardiotoxicity remains insufficient.

PURPOSE

In present study, our group's innovative concept of toxicological evidence chain (TEC) was applied to reveal the cardiac toxicity mechanism of PPT by targeted metabolomics, TMT-based quantitative proteomics and western blot.

METHODS

The injury phenotype evidence (IPE) acquired from the toxicity manifestations, such as weight and behavior observation of Sprague-Dawley rat. The damage to rat hearts were assessed through histopathological examination and myocardial enzymes levels, which were defined as Adverse Outcomes Evidence (AOE). The damage to rat hearts was assessed through histopathological examination and myocardial enzyme levels, which were defined as evidence of adverse outcomes.Overall measurements of targeted metabolomics based on energy metabolism and TMT-based quantitative proteomics were obtained after exposure to PPT to acquire the Toxic Event Evidence (TEE). The mechanism of cardiac toxicity was speculated based on the integrated analysis of targeted metabolomics and TMT-based quantitative proteomics, which was verified by western blot.

RESULTS

The results indicated that exposure to PPT could result in significant elevation of myocardial enzymes and pathological alterations in rat hearts. In addition, we found that PPT caused disorders in cardiac energy metabolism, characterized by a decrease in energy metabolism fuels. TMT-based quantitative proteomics revealed that the PPAR (Peroxisome proliferators-activated receptor) signaling pathway needs further study. It is worth noting that PPT may suppress the expression of SIRT1, subsequently inhibiting AMPK, decreasing the expression of PGC-1α, PPARα and PPARγ. This results in disorders of glucose oxidation, glycolysis and ketone body metabolism. Additionally, the increase in the expression of p-IKK and p-IκBα, leads to the nuclear translocation of NF-κB p65 from the cytosol, thus triggering inflammation.

CONCLUSION

This study comprehensively evaluated cardiac toxicity of PPT and initially revealed the mechanism of cardiotoxicity,suggesting that PPT induced disorders of energy metabolism and inflammation via SIRT1/PPAR/NF-κB axis, potentially contributing to cardiac injury.

The noncanonical NFκB pathway: Regulatory mechanisms in health and disease

The noncanonical NFκB signaling pathway mediates the biological functions of diverse cell survival, growth, maturation, and differentiation factors that are important for the development and maintenance of hematopoietic cells and immune organs. Its dysregulation is associated with a number of immune pathologies and malignancies. Originally described as the signaling pathway that controls the NFκB family member RelB, we now know that noncanonical signaling also controls NFκB RelA and cRel. Here, we aim to clarify our understanding of the molecular network that mediates noncanonical NFκB signaling and review the human diseases that result from a deficient or hyper-active noncanonical NFκB pathway. It turns out that dysregulation of RelA and cRel, not RelB, is often implicated in mediating the resulting pathology. This article is categorized under: Immune System Diseases > Molecular and Cellular Physiology Cancer > Molecular and Cellular Physiology Immune System Diseases > Stem Cells and Development.

Open questions in the NF-κB field

A variety of stress signals leads to activation of the inducible transcription factor NF-κB, one of the master regulators of the innate immune response. Despite a wealth of information available on the NF-κB core components and its control by different activation pathways and negative feedback loops, several levels of complexity hamper our understanding of the system. This has also contributed to the limited success of NF-κB inhibitors in the clinic and explains some of their unexpected effects. Here we consider the molecular and cellular events generating this complexity at all levels and point to a number of unresolved questions in the field. We also discuss potential future experimental and computational strategies to provide a deeper understanding of NF-κB and its coregulatory signaling networks.

NRF2 interacts with distal enhancer and inhibits nitric oxide synthase 2 expression in KRAS-driven pancreatic cancer cells

Nitric oxide is a pleiotropic free radical produced by three nitric oxide synthases (NOS1-3), of which inducible NOS2 is involved in tumor initiation and progression. In this study, RNA-seq, ChIP-seq and qRT-PCR experiments combined with bioinformatic analyses showed that NRF2 is a repressor of NOS2 gene by maintaining a distal enhancer located 22 kb downstream of TSS in an inactive state. Deletion of NRF2 leads to activation of the enhancer, which exerts a pioneering function before it is fully activated. Specifically, NRF2 controls the expression of NOS2 in response to intracellular oxidative stress and extracellular oxygen pressure. We found that abrogation of NOS2 expression by siRNAs partially reduced the ability of WT Panc-1 cells to form 3D spheroids, but strongly reduced the formation of 3D spheroids by NRF2-depleted Panc-1 cells. Mechanistically, this effect correlates with the finding that NOS2 and nitric oxide stimulate epithelial-to-mesenchymal transition in NRF2-depleted Panc-1 and MIA PaCa-2 cells. We also found that knockdown of NOS2 leads to blockade of 3D matrigel invasion of NRF2-depleted PDAC cells, demonstrating that a short-circuit in the reciprocal regulation of NOS2 and NRF2 attenuates the malignancy of PDAC cells. In summary, we show for the first time that: (i) NRF2 is a suppressor of NOS2 in pancreatic cancer cells; (ii) NRF2 binds to and inactivates an enhancer located 22 kb downstream of TSS of the NOS2 gene; (iii) activation of NOS2 requires suppression of NRF2; (iv) NOS2 is required for NRF2-depleted Panc-1 cells to maintain their malignancy and invasiveness.

Reactive oxygen species, toxicity, oxidative stress, and antioxidants: chronic diseases and aging

A physiological level of oxygen/nitrogen free radicals and non-radical reactive species (collectively known as ROS/RNS) is termed oxidative eustress or "good stress" and is characterized by low to mild levels of oxidants involved in the regulation of various biochemical transformations such as carboxylation, hydroxylation, peroxidation, or modulation of signal transduction pathways such as Nuclear factor-κB (NF-κB), Mitogen-activated protein kinase (MAPK) cascade, phosphoinositide-3-kinase, nuclear factor erythroid 2-related factor 2 (Nrf2) and other processes. Increased levels of ROS/RNS, generated from both endogenous (mitochondria, NADPH oxidases) and/or exogenous sources (radiation, certain drugs, foods, cigarette smoking, pollution) result in a harmful condition termed oxidative stress ("bad stress"). Although it is widely accepted, that many chronic diseases are multifactorial in origin, they share oxidative stress as a common denominator. Here we review the importance of oxidative stress and the mechanisms through which oxidative stress contributes to the pathological states of an organism. Attention is focused on the chemistry of ROS and RNS (e.g. superoxide radical, hydrogen peroxide, hydroxyl radicals, peroxyl radicals, nitric oxide, peroxynitrite), and their role in oxidative damage of DNA, proteins, and membrane lipids. Quantitative and qualitative assessment of oxidative stress biomarkers is also discussed. Oxidative stress contributes to the pathology of cancer, cardiovascular diseases, diabetes, neurological disorders (Alzheimer's and Parkinson's diseases, Down syndrome), psychiatric diseases (depression, schizophrenia, bipolar disorder), renal disease, lung disease (chronic pulmonary obstruction, lung cancer), and aging. The concerted action of antioxidants to ameliorate the harmful effect of oxidative stress is achieved by antioxidant enzymes (Superoxide dismutases-SODs, catalase, glutathione peroxidase-GPx), and small molecular weight antioxidants (vitamins C and E, flavonoids, carotenoids, melatonin, ergothioneine, and others). Perhaps one of the most effective low molecular weight antioxidants is vitamin E, the first line of defense against the peroxidation of lipids. A promising approach appears to be the use of certain antioxidants (e.g. flavonoids), showing weak prooxidant properties that may boost cellular antioxidant systems and thus act as preventive anticancer agents. Redox metal-based enzyme mimetic compounds as potential pharmaceutical interventions and sirtuins as promising therapeutic targets for age-related diseases and anti-aging strategies are discussed.

NF-kB and the CLL microenvironment

Chronic lymphocytic leukemia (CLL) is the most prevalent type of leukemia in the western world. Despite the positive clinical effects of new targeted therapies, CLL still remains an incurable and refractory disease and resistance to treatments are commonly encountered. The Nuclear Factor-Kappa B (NF-κB) transcription factor has been implicated in the pathology of CLL, with high levels of NF-κB associated with disease progression and drug resistance. This aberrant NF-κB activation can be caused by genetic mutations in the tumor cells and microenvironmental factors, which promote NF-κB signaling. Activation can be induced via two distinct pathways, the canonical and non-canonical pathway, which result in tumor cell proliferation, survival and drug resistance. Therefore, understanding how the CLL microenvironment drives NF-κB activation is important for deciphering how CLL cells evade treatment and may aid the development of novel targeting therapeutics. The CLL microenvironment is comprised of various cells, including nurse like cells, mesenchymal stromal cells, follicular dendritic cells and CD4+ T cells. By activating different receptors, including the B cell receptor and CD40, these cells cause overactivity of the canonical and non-canonical NF-κB pathways. Within this review, we will explore the different components of the CLL microenvironment that drive the NF-κB pathway, investigating how this knowledge is being translated in the development of new therapeutics.

NFκB signaling in T cell memory

Memory T cells play an essential role in protecting against infectious diseases and cancer and contribute to autoimmunity and transplant rejection. Understanding how they are generated and maintained in the context of infection or vaccination holds promise to improve current immune-based therapies. At the beginning of any immune response, naïve T cells are activated and differentiate into cells with effector function capabilities. In the context of infection, most of these cells die once the pathogenic antigen has been cleared. Only a few of them persist and differentiate into memory T cells. These memory T cells are essential to host immunity because they are long-lived and can perform effector functions immediately upon re-infection. How a cell becomes a memory T cell and continues being one for months and even years past the initial infection is still not fully understood. Recent reviews have thoroughly discussed the transcriptional, epigenomic, and metabolic mechanisms that govern T cell memory differentiation. Yet much less is known of how signaling pathways that are common circuitries of multiple environmental signals regulate T cell outcome and, precisely, T cell memory. The function of the NFκB signaling system is perhaps best understood in innate cells. Recent findings suggest that NFκB signaling plays an essential and unique role in generating and maintaining CD8 T cell memory. This review aims to summarize these findings and discuss the remaining questions in the field.

Free Radicals and Oxidative Stress: Signaling Mechanisms, Redox Basis for Human Diseases, and Cell Cycle Regulation

Free radicals contain one or more unpaired electrons in their valence shell, thus making them unstable, short-lived, and highly reactive species. Excessive generation of these free radicals ultimately leads to oxidative stress causing oxidation and damage to significant macromolecules in the living system and essentially disrupting signal transduction pathways and antioxidants equilibrium. At lower concentrations, ROS serves as "second messengers," influencing many physiological processes in the cell. However, higher concentrations beyond cell capacity cause oxidative stress, contributing to human pathologies such as diabetes, cancer, Parkinson's disease, cardiovascular diseases, cataract, asthma, hypertension, atherosclerosis, arthritis, and Alzheimer's disease. Signaling pathways such as NF-κB, MAPKs, PI3K/Akt/ mTOR, and Keap1-Nrf2- ARE modulate the detrimental effects of oxidative stress by increasing the expression of cellular antioxidant defenses, phase II detoxification enzymes, and decreased production of ROS. Free radicals such as H2O2 are indeed needed for the advancement of the cell cycle as these molecules influence DNA, proteins, and enzymes in the cell cycle pathway. In the course of cell cycle progression, the cellular redox environment becomes more oxidized, moving from the G1 phase, becoming higher in G2/M and moderate in the S phase. Signals in the form of an increase in cellular pro-oxidant levels are required, and these signals are often terminated by a rise in the amount of antioxidants and MnSOD with a decrease in the level of cyclin D1 proteins. Therefore, understanding the mechanism of cell cycle redox regulation will help in the therapy of many diseases.

A Vitamin D-RelB/NF-κB Pathway Limits Chandipura Virus Multiplication by Rewiring the Homeostatic State of Autoregulatory Type 1 IFN-IRF7 Signaling

Besides its functions in the skeletomuscular system, vitamin D is known to alleviate viral-inflicted pathologies. However, the mechanism underlying protective vitamin D function remains unclear. We examined the role of vitamin D in controlling cellular infections by Chandipura virus, an RNA virus implicated in human epidemics. How immune signaling pathways, including those regulating NF-κB and IFN regulatory factors (IRFs), are activated in virus-infected cells has been well studied. Our investigation involving human- and mouse-derived cells revealed that vitamin D instructs the homeostatic state of these antiviral pathways, leading to cellular resilience to subsequent viral infections. In particular, vitamin D provoked autoregulatory type 1 IFN-IRF7 signaling even in the absence of virus infection by downmodulating the expression of the IFN-inhibitory NF-κB subunit RelB. Indeed, RelB deficiency rendered vitamin D treatment redundant, whereas IRF7 depletion abrogated antiviral vitamin D action. In sum, immune signaling homeostasis appears to connect micronutrients to antiviral immunity at the cellular level. The proposed link may have a bearing on shaping public health policy during an outbreak.

Selective EZH2 inhibitor zld1039 alleviates inflammation in cisplatin-induced acute kidney injury partially by enhancing RKIP and suppressing NF-κB p65 pathway

Enhancer of zeste homolog 2 (EZH2), a component of polycomb repressive complex 2 (PRC2), is a histone lysine methyltransferase mediating trimethylation of histone H3 at lysine 27 (H3K27me3), which is a repressive marker at the transcriptional level. EZH2 sustains normal renal function and its overexpression has bad properties. Inhibition of EZH2 overexpression exerts protective effect against acute kidney injury (AKI). A small-molecule compound zld1039 has been developed as an efficient and selective EZH2 inhibitor. In this study, we evaluated the efficacy of zld1039 in the treatment of cisplatin-induced AKI in mice. Before injection of cisplatin (20 mg/kg, i.p.), mice were administered zld1039 (100, 200 mg/kg, i.g.) once, then in the following 3 days. We found that cisplatin-treated mice displayed serious AKI symptoms, evidenced by kidney dysfunction and kidney histological injury, accompanied by EZH2 upregulation in the nucleus of renal tubular epithelial cells. Administration of zld1039 dose-dependently alleviated renal dysfunction as well as the histological injury, inflammation and cell apoptosis in cisplatin-treated mice. We revealed that zld1039 administration exerted an anti-inflammatory effect in kidney of cisplatin-treated mice via H3K27me3 inhibition, raf kinase inhibitor protein (RKIP) upregulation and NF-κB p65 repression. In the cisplatin-treated mouse renal tubular epithelial (TCMK-1) cells, silencing of RKIP with siRNA did not abolish the anti-inflammatory effect of EZH2 inhibition, suggesting that RKIP was partially involved in the anti-inflammatory effect of zld1039. Collectively, EZH2 inhibition alleviates inflammation in cisplatin-induced mouse AKI via upregulating RKIP and blocking NF-κB p65 signaling in cisplatin-induced AKI. The potent and selective EZH2 inhibitor zld1039 has the potential as a promising agent for the treatment of AKI.

The microdissected gene expression landscape of nasopharyngeal cancer reveals vulnerabilities in FGF and noncanonical NF-κB signaling

Nasopharyngeal cancer (NPC) is an Epstein-Barr virus (EBV)-positive epithelial malignancy with an extensive inflammatory infiltrate. Traditional RNA-sequencing techniques uncovered only microenvironment signatures, while the gene expression of the tumor epithelial compartment has remained a mystery. Here, we use Smart-3SEQ to prepare transcriptome-wide gene expression profiles from microdissected NPC tumors, dysplasia, and normal controls. We describe changes in biological pathways across the normal to tumor spectrum and show that fibroblast growth factor (FGF) ligands are overexpressed in NPC tumors, while negative regulators of FGF signaling, including SPRY1, SPRY2, and LGALS3, are down-regulated early in carcinogenesis. Within the NF-κB signaling pathway, the critical noncanonical transcription factors, RELB and NFKB2, are enriched in the majority of NPC tumors. We confirm the responsiveness of EBV-positive NPC cell lines to targeted inhibition of these pathways, reflecting the heterogeneity in NPC patient tumors. Our data comprehensively describe the gene expression landscape of NPC and unravel the mysteries of receptor tyrosine kinase and NF-κB pathways in NPC.

Antimicrobial Activity of Brassica rapa L. Flowers Extract on Gastrointestinal Tract Infections and Antiulcer Potential Against Indomethacin-Induced Gastric Ulcer in Rats Supported by Metabolomics Profiling

INTRODUCTION

The gastrointestinal tract (GIT) is vulnerable to various diseases. In this study, we explored the therapeutic effects of Brassica rapa flower extract (BRFE) on GIT diseases.

METHODS

Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was used for phytochemical identification of the compounds in BRFE. The antibacterial activity of BRFE was investigated, and its impact on the bacterial outer and inner membrane permeability and membrane depolarization (using flow cytometry) was studied. In addition, the immunomodulatory activity of BRFE was investigated in vitro on lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Furthermore, the anti-inflammatory activity of BRFE was investigated by histopathological examination and qRT-PCR on indomethacin-induced gastric ulcers in rats.

RESULTS AND DISCUSSION

LC-ESI-MS/MS phytochemically identified 57 compounds in BRFE for the first time. BRFE displayed antibacterial activity against bacteria that cause GIT infections, with increasing outer and inner membrane permeability. However, membrane depolarization was unaffected. BRFE also exhibited immunomodulatory activity in LPS-stimulated PBMCs by attenuating the upregulation of cyclooxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α), and nuclear factor kappa B (NF-κB) gene expression compared with untreated LPS-stimulated PBMCs. In addition, BRFE exhibited anti-inflammatory activity required for maintaining gastric mucosa homeostasis by decreasing neutrophil infiltration with subsequent myeloperoxidase production, in addition to an increase in glutathione peroxidase (GPx) activity. Histopathological findings presented the gastroprotective effects of BRFE, as a relatively normal stomach mucosa was found in treated rats. In addition, BRFE modulated the expression of genes encoding IL-10, NF-κB, GPx, and myeloperoxidase (MPO).

CONCLUSION

BRFE can be a promising source of therapeutic agents for treatment of GIT diseases.

Determinants of Ligand Specificity and Functional Plasticity in Type I Interferon Signaling

The Type I Interferon family of cytokines all act through the same cell surface receptor and induce phosphorylation of the same subset of response regulators of the STAT family. Despite their shared receptor, different Type I Interferons have different functions during immune response to infection. In particular, they differ in the potency of their induced anti-viral and anti-proliferative responses in target cells. It remains not fully understood how these functional differences can arise in a ligand-specific manner both at the level of STAT phosphorylation and the downstream function. We use a minimal computational model of Type I Interferon signaling, focusing on Interferon-α and Interferon-β. We validate the model with quantitative experimental data to identify the key determinants of specificity and functional plasticity in Type I Interferon signaling. We investigate different mechanisms of signal discrimination, and how multiple system components such as binding affinity, receptor expression levels and their variability, receptor internalization, short-term negative feedback by SOCS1 protein, and differential receptor expression play together to ensure ligand specificity on the level of STAT phosphorylation. Based on these results, we propose phenomenological functional mappings from STAT activation to downstream anti-viral and anti-proliferative activity to investigate differential signal processing steps downstream of STAT phosphorylation. We find that the negative feedback by the protein USP18, which enhances differences in signaling between Interferons via ligand-dependent refractoriness, can give rise to functional plasticity in Interferon-α and Interferon-β signaling, and explore other factors that control functional plasticity. Beyond Type I Interferon signaling, our results have a broad applicability to questions of signaling specificity and functional plasticity in signaling systems with multiple ligands acting through a bottleneck of a small number of shared receptors.

Fibroblast-specific IKKβ deficiency ameliorates angiotensin II-induced adverse cardiac remodeling in mice

Cardiac inflammation and fibrosis contribute significantly to hypertension-related adverse cardiac remodeling. IκB kinase β (IKK-β), a central coordinator of inflammation through activation of NF-κB, has been demonstrated as a key molecular link between inflammation and cardiovascular disease. However, the cell-specific contribution of IKK-β signaling toward adverse cardiac remodeling remains elusive. Cardiac fibroblasts are one of the most populous nonmyocyte cell types in the heart that play a key role in mediating cardiac fibrosis and remodeling. To investigate the function of fibroblast IKK-β, we generated inducible fibroblast-specific IKK-β–deficient mice. Here, we report an important role of IKK-β in the regulation of fibroblast functions and cardiac remodeling. Fibroblast-specific IKK-β–deficient male mice were protected from angiotensin II–induced cardiac hypertrophy, fibrosis, and macrophage infiltration. Ablation of fibroblast IKK-β inhibited angiotensin II–stimulated fibroblast proinflammatory and profibrogenic responses, leading to ameliorated cardiac remodeling and improved cardiac function in IKK-β–deficient mice. Findings from this study establish fibroblast IKK-β as a key factor regulating cardiac fibrosis and function in hypertension-related cardiac remodeling.

Pleiotropy enables specific and accurate signaling in the presence of ligand cross talk

Living cells sense their environment through the binding of extracellular molecular ligands to cell surface receptors. Puzzlingly, vast numbers of signaling pathways exhibit a high degree of cross talk between different signals whereby different ligands act through the same receptor or shared components downstream. It remains unclear how a cell can accurately process information from the environment in such cross-wired pathways. We show that a feature which commonly accompanies cross talk-signaling pleiotropy (the ability of a receptor to produce multiple outputs)-offers a solution to the cross-talk problem. In a minimal model we show that a single pleiotropic receptor can simultaneously identify and accurately sense the concentrations of arbitrary unknown ligands present individually or in a mixture. We calculate the fundamental limits of the signaling specificity and accuracy of such signaling schemes. The model serves as an elementary "building block" toward understanding more complex cross-wired receptor-ligand signaling networks.

Cytokines and pregnancy: Potential regulation by histone deacetylases

Cytokines are important regulators of pregnancy and parturition. Aberrant expression of proinflammatory cytokines during pregnancy contributes towards preterm labor, pre-eclampsia, and gestational diabetes mellitus. The regulation of cytokine expression in human cells is highly complex, involving interactions between environment, transcription factors, and feedback mechanisms. Recent developments in epigenetic research have made tremendous advancements in exploring histone modifications as a key epigenetic regulator of cytokine expression and the effect of their signaling molecules on various organ systems in the human body. Histone acetylation and subsequent deacetylation by histone deacetylases (HDACs) are major epigenetic regulators of protein expression in the human body. The expression of various proinflammatory cytokines, their role in normal and abnormal pregnancy, and their epigenetic regulation via HDACs will be discussed in this review.

The Impact of Acute or Chronic Alcohol Intake on the NF-κB Signaling Pathway in Alcohol-Related Liver Disease

Ethanol misuse is frequently associated with a multitude of profound medical conditions, contributing to health-, individual- and social-related damage. A particularly dangerous threat from this classification is coined as alcoholic liver disease (ALD), a liver condition caused by prolonged alcohol overconsumption, involving several pathological stages induced by alcohol metabolic byproducts and sustained cellular intoxication. Molecular, pathological mechanisms of ALD principally root in the innate immunity system and are especially associated with enhanced functionality of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. NF-κB is an interesting and convoluted DNA transcription regulator, promoting both anti-inflammatory and pro-inflammatory gene expression. Thus, the abundancy of studies in recent years underlines the importance of NF-κB in inflammatory responses and the mechanistic stimulation of inner molecular motifs within the factor components. Hereby, in the following review, we would like to put emphasis on the correlation between the NF-κB inflammation signaling pathway and ALD progression. We will provide the reader with the current knowledge regarding the chronic and acute alcohol consumption patterns, the molecular mechanisms of ALD development, the involvement of the NF-κB pathway and its enzymatic regulators. Therefore, we review various experimental in vitro and in vivo studies regarding the research on ALD, including the recent active compound treatments and the genetic modification approach. Furthermore, our investigation covers a few human studies.

Upregulation of iNOS Protects Cyclic Mechanical Stretch-Induced Cell Death in Rat Aorta Smooth Muscle Cells

Aortic dissection and aneurysm are associated with abnormal hemodynamic loads originating from hypertension. Our previous study demonstrated that cyclic mechanical stretch (CMS, mimicked hypertension) caused the death of rat aortic smooth muscle cells (RASMCs) in a mitogen activated-protein kinases (MAPKs)-dependent manner. The current study investigated the effects of inducible nitric oxide synthase (iNOS) on CMS-induced RASMC death. cDNA microarrays for CMS-treated RASMCs showed that iNOS expression levels were increased in response to CMS. Real-time polymerase chain reaction (PCR) analysis demonstrated that this increase was p38 MAPK (p38)-dependent. NO production was also increased. This increase could be inhibited by p38 and iNOS inhibitors. Thus, CMS-induced iNOS synthesized NO. CMS-induced cell death in RASMCs was increased by the iNOS inhibitor but abrogated by the long-acting NO donor DETA-NONOate. Increased iNOS expression was confirmed in the abdominal aortic constriction mouse model. Signal transducers and activators of transcription 1 (STAT1) was activated in stretched RASMCs, and iNOS expression and NO production were inhibited by the STAT1 inhibitor nifuroxazide. Our findings suggest that RASMCs were protected by iNOS from CMS-stimulated cell death through the STAT1 and p38 signal pathways independently.

TgROP18 targets IL20RB for host-defense-related-STAT3 activation during Toxoplasma gondii infection

Background

Toxoplasma gondii is an opportunistic protozoan infecting almost one-third of the world’s population. Toxoplasma gondii rhoptry protein 18 (TgROP18) is a key virulence factor determining the parasite’s acute virulence and is secreted into host cells during infection. We previously identified the interaction of TgROP18 and host cell immune-related receptor protein IL20RB, and observed the activation of STAT3 in human keratinocytes (HaCaT) cells infected by the rop16 knockout RH strain, though TgROP16 is regarded as being responsible for host STAT3 activation during T. gondii invasion. Therefore, we hypothesize TgROP18 can activate host STAT3 through binding to IL20RB.

Methods

CRISPR-CAS9 technology was used to generate the ROP16 and ROP18 double knockout RH strain, RH-∆rop16∆rop18. SDS-PAGE and western blot were used to detect STAT3 activation in different HaCaT cells with high endogenous IL20RB expression treated with T. gondii tachyzoites infection, recombinant ROP18, or IL-20. FRET and co-immunoprecipitation (Co-IP) was used to detect the protein-protein interaction.

Results

We observed that TgROP18 was involved in a synergic activation of the host JAK/STAT3 pathway together with TgROP16 in human HaCaT cells infected with T. gondii or treated with recombinant TgROP18 protein, stimulating host proinflammatory immune responses such as expression of TNF-α. The effect of recombinant ROP18 on STAT3 phosphorylation was presented in a dose-dependent manner. Additionally, TgROP18 was identified to target IL20RB on its extracellular domain. When we treated different cell lines with the recombinant ROP18, STAT3 phosphorylation could only be observed in the cells with endogenous IL20RB expression, such as HaCaT cells.

Conclusions

These findings indicate that TgROP18-IL20RB interaction upon T. gondii invasion was involved in STAT3 activation, which is associated with host cell defense.

Integrative analysis suggests cell type-specific decoding of NF-κB dynamics

The complex signaling dynamics of transcription factors can encode both qualitative and quantitative information about the extracellular environment, which increases the information transfer capacity and potentially supports accurate cellular decision-making. An important question is how these signaling dynamics patterns are translated into functionally appropriate gene regulation programs. To address this question for transcription factors of the nuclear factor κB (NF-κB) family, we profiled the single-cell dynamics of two major NF-κB subunits, RelA and c-Rel, induced by a panel of pathogen-derived stimuli in immune and nonimmune cellular contexts. Diverse NF-κB-activating ligands produced different patterns of RelA and c-Rel signaling dynamic features, such as variations in duration or time-integrated activity. Analysis of nascent transcripts delineated putative direct targets of NF-κB as compared to genes controlled by other transcriptional and posttranscriptional mechanisms and showed that the transcription of more than half of the induced genes was tightly linked to specific dynamic features of NF-κB signaling. Fibroblast and macrophage cell lines shared a cluster of such "NF-κB dynamics-decoding" genes, as well as cell type-specific decoding genes. Dissecting the subunit specificity of dynamics-decoding genes suggested that target genes were most often linked to both RelA and c-Rel or to RelA alone. Thus, our analysis reveals the cell type-specific interpretation of pathogenic information through the signaling dynamics of NF-κB.

Paricalcitol improves experimental autoimmune encephalomyelitis (EAE) by suppressing inflammation via NF-κB signaling

Multiple sclerosis (MS) is known as an autoimmune disease in the central nervous system (CNS) characterized by motor deficits, pain, fatigue, cognitive impairment, and sensory and visual dysfunction. MS is considered to be resulted from significant inflammatory response. Paricalcitol (Pari) is a vitamin D2 analogue, which has been indicated to show anti-inflammatory activities in kidney and heart diseases. In the present study, if Pari could ameliorate the experimental autoimmune encephalomyelitis (EAE) was investigated. Here, the C57BL/6 mice were immunized using myelin oligodendrocyte glycoprotein 35-55 (MOG_35-55). Subsequently, Pari was intraperitoneally injected into the mice. As for in vitro analysis, RAW264.7 and Jurkat cells were incubated with Pari together with corresponding stimulus. The results indicated that Pari administration reduced the paralytic severity, neuropathology and apoptosis in MOG-treated mice compared to the MOG single group. Pari also exhibited a significantly inhibitory effect on immune cell infiltration, glial cell activation, expression of pro-inflammatory factors and the activation of nuclear factor κB (NF-κB). The expression of pro-inflammatory regulators and the translocation of NF-κB from cytoplasm into nuclear in RAW264.7 and Jurkat cells under specific stimulation was clearly down-regulated by Pari incubation. Furthermore, we found that suppressing NF-κB with its inhibitor combined with Pari could further reduce the expression of pro-inflammatory factors and associated proteins. These data illustrated that Pari could diminish MOG-triggered EAE, as well as macrophages and T cells activation through blocking NF-κB activation. Collectively, Pari might have therapeutic effects in mouse models with MS.

A universal reporter cell line for bioactivity evaluation of engineered cytokine products

Engineered cytokine products represent a growing class of therapeutic proteins which need to be tested for biological activity at various stages of pharmaceutical development. In most cases, dedicated biological assays are established for different products, in a process that can be time-consuming and cumbersome. Here we describe the development and implementation of a universal cell-based reporter system for various classes of immunomodulatory proteins. The novel system capitalizes on the fact that the signaling of various types of pro-inflammatory agents (e.g., cytokines, chemokines, Toll-like receptor agonists) may involve transcriptional activation by NF-κB. Using viral transduction, we generated stably-transformed cell lines of B or T lymphocyte origin and compared the new reporter cell lines with conventional bioassays. The experimental findings with various interleukins and with members of the TNF superfamily revealed that the newly-developed “universal” bioassay method yielded bioactivity data which were comparable to the ones obtained with dedicated conventional methods. The engineered cell lines with reporters for NF-κB were tested with several antibody-cytokine fusions and may be generally useful for the characterization of novel immunomodulatory products. The newly developed methodology also revealed a mechanism for cytokine potentiation, based on the antibody-mediated clustering of TNF superfamily members on tumor-associated extracellular matrix components.

CTGF Triggers Rat Astrocyte Activation and Astrocyte-Mediated Inflammatory Response in Culture Conditions

To improve clinical outcomes for patients with traumatic brain injury (TBI), it is necessary to explore the mechanism of traumatic brain injury (TBI)-induced neuroinflammation. Connective tissue growth factors (CTGF) have been reported to be involved in the process of inflammatory response or tissue repair, whereas whether and how CTGF participates in the astrocyte-mediated inflammation after TBI remains unclear. In the present study, the TBI-induced activation of astrocytes and augmentation of inflammatory response were simulated by stimulating rat astrocytes with TGF-β1 or CTGF in cultured conditions. TGF-β1 and CTGF both upregulated the expression of GFAP in astrocytes and facilitated the production of inflammatory cytokines and chemokines. Activation of astrocytes by CTGF is in an autocrine manner. According to the results of Boyden chamber assay, CTGF enhanced the recruitment of peripheral blood mononuclear cells (PBMCs) by reactive astrocytes. Besides, CTGF-mediated activation of astrocytes and augmentation of inflammatory response can be terminated by the inhibitor of ASK1 or p38 and JNK. Thus, our data suggested that CTGF could activate astrocytes in an autocrine manner and promote astrocyte-mediated inflammatory response by triggering the ASK1-p38/JNK-NF-κB/AP-1 pathways in astrocytes. Collectively, our study provided evidence that astrocyte-secreted CTGF serves as an amplifier of neuroinflammatory and could be a potential target for alleviating TBI-induced inflammation.

Systematic Analysis of Monoterpenes: Advances and Challenges in the Treatment of Peptic Ulcer Diseases

Peptic ulcer disease (PUD) is a multifactorial and complex disease caused by an imbalance of protective and aggressive factors (endogenous and exogenous). Despite advances in recent years, it is still responsible for substantial mortality and triggering clinical problems. Over the last decades, the understanding of PUD has changed a lot with the discovery of Helicobacter pylori infection. However, this disease continues to be a challenge due to side-effects, incidence of relapse from use of various anti-ulcer medicines, and the rapid appearance of antimicrobial resistance with current H. pylori therapies. Consequently, there is the need to identify more effective and safe anti-ulcer agents. The search for new therapies with natural products is a viable alternative and has been encouraged. The literature reports the importance of monoterpenes based on the extensive pharmacological action of this class, including wound healing and anti-ulcerogenic agents. In the present study, 20 monoterpenes with anti-ulcerogenic properties were evaluated by assessing recent in vitro and in vivo studies. Here, we review the anti-ulcer effects of monoterpenes against ulcerogenic factors such as ethanol, nonsteroidal anti-inflammatory drugs (NSAIDs), and Helicobacter pylori, highlighting challenges in the field.

Substrate complex competition is a regulatory motif that allows NFκB RelA to license but not amplify NFκB RelB

Signaling pathways often share molecular components, tying the activity of one pathway to the functioning of another. In the NFκB signaling system, distinct kinases mediate inflammatory and developmental signaling via RelA and RelB, respectively. Although the substrates of the developmental, so-called noncanonical, pathway are induced by inflammatory/canonical signaling, crosstalk is limited. Through dynamical systems modeling, we identified the underlying regulatory mechanism. We found that as the substrate of the noncanonical kinase NIK, the nfkb2 gene product p100, transitions from a monomer to a multimeric complex, it may compete with and inhibit p100 processing to the active p52. Although multimeric complexes of p100 (IκBδ) are known to inhibit preexisting RelA:p50 through sequestration, here we report that p100 complexes can inhibit the enzymatic formation of RelB:p52. We show that the dose-response systems properties of this complex substrate competition motif are poorly accounted for by standard Michaelis-Menten kinetics, but require more detailed mass action formulations. In sum, although tonic inflammatory signaling is required for adequate expression of the noncanonical pathway precursors, the substrate complex competition motif identified here can prevent amplification of the active RelB:p52 dimer in elevated inflammatory conditions to ensure reliable RelB-dependent developmental signaling independent of inflammatory context.

Alanyl-glutamine ameliorates lipopolysaccharide-induced inflammation and barrier function injury in bovine jejunum epithelial cells

The aim of this study was to investigate the effects of alanyl-glutamine (Ala-Gln) on the regulation of lipopolysaccharide (LPS)-induced inflammation and barrier function in bovine jejunum epithelial cells (BJECs). BJECs were exposed (or not) to 1 μg/mL LPS for 24 h to generate a pro-inflammatory model. The cells were then treated with different concentrations of Ala-Gln (0.25, 0.5, 1.0, 2.0, or 4.0 mmol/L) to detect any regulatory effects on the inflammation and barrier function of BJECs. LPS decreased cell viability and enhanced the production of the pro-inflammatory cytokines interleukin (IL)-6 and IL-8. LPS induced inflammation and damaged the barrier function of BJECs, as evidenced by up-regulated mRNA and protein expression of inflammatory factors and down-regulated expression of tight junction proteins. Conversely, Ala-Gln rescued the decrease in cell viability and prevented the accumulation of ILs after LPS exposure by reducing the mRNA and protein expression levels of inflammatory factors. In addition, Ala-Gln induced the mRNA and protein expression of multiple tight junction proteins, and thus reconstituted the barrier function of BJECs. In conclusion, Ala-Gln attenuates injury from inflammation and repairs damaged intestinal barrier induced with LPS, suggesting its potential as a therapeutic agent against intestinal inflammation in mammals.

Gastroprotective effect of limonene in rats: Influence on oxidative stress, inflammation and gene expression

BACKGROUND

In an increasing search for natural products that may heal the ulcers and avoid its recurrence, limonene appears as a promising candidate.

HYPOTHESIS/PURPOSE

The present study aimed to investigate the protective effect of limonene in ethanol-induced gastric ulcers, in addition, to investigate the involvement of antioxidant and anti-inflammatory activities, besides the modulation of gene expression.

STUDY DESIGN

Male Wistar rats were orally treated with vehicle (8% tween 80), carbenoxolone (100 mg/kg) or limonene (25, 50 or 100 mg/kg) and then orally received ethanol to induce gastric ulcers formation.

METHODS

The activity of myeloperoxidase (MPO) was measured. Levels of glutathione (GSH) and activities of glutathione peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD) were measured. We investigated the anti-inflammatory effect of limonene measuring the levels of pro-inflammatory cytokines tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), interleukin-1β (IL-1β) and anti-inflammatory cytokine interleukin-10 (IL-10) by ELISA. Additionally, we investigate through real-time PCR (qPCR) the gene expression of nuclear factor-kappa B (Nf-κb), Gpx, Il-1β, Mpo, and Il-10.

RESULTS

Our results showed that limonene 50 mg/kg was the lowest effective dose, offering 93% of reduction in gastric ulcer area compared with the vehicle. There was an increase in mucus production and higher preservation of gastric mucosa integrity after treatment with limonene.There was a reduction in the MPO activity, a biomarker of neutrophils infiltration, and an increase in GPx activity, suggesting an antioxidant effect. Limonene displayed anti-inflammatory activity through decreasing the levels of TNF-a, IL-6, and IL-1β and increasing the level of IL-10. Limonene could down-regulate the expression of Nf-κb, Il-1β, and Mpo and up-regulate the expression of Gpx.

CONCLUSION

Our results demonstrate that oral treatment with limonene exerts gastroprotection through local mucosal defense mechanisms, such as increasing the mucus production, modulation of the oxidative stress and inflammatory response and inhibition of Nf-κb expression.

Anti-Inflammatory Activity of Populus deltoides Leaf Extract via Modulating NF-κB and p38/JNK Pathways

Populus deltoides, known as eastern cottonwood, has been commonly used as a medicinal plant. The aim of the present study was to investigate the mechanism underlying the anti-inflammatory activity of P. deltoides leaf extract (PLE). PLE effectively inhibited the expression of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, but not that of cyclooxygenase-2 (COX-2) and prostaglandin E2. Proinflammatory tumor necrosis factor alpha (TNF-α) levels were also reduced by the extract. PLE inhibited the phosphorylation of nuclear factor-kappa B (NF-κB) and inhibitor of Kappa Bα (IκBα), and blunted LPS-triggered enhanced nuclear translocation of NF-κB p65. In mitogen-activated protein kinase (MAPK) signaling, PLE effectively decreased the phosphorylation of p38 and c-Jun N-terminal protein kinase (JNK), but not of extracellular signal-regulated kinase 1/2 (ERK1/2). Taken together, these results suggest that anti-inflammatory activity of P. deltoides leaf extract might be driven by iNOS and NO inhibition mediated by modulation of the NF-κB and p38/JNK signaling pathways.

Expression of Inflammatory-Related NFκB Genes in Iranian Patients with Pterygium: A Case-Control Study

Pterygium is one of the most common eye conditions without any clear etiology. Some studies have suggested an association between sun exposure and pterygium, but others have proposed the role of genetic variations in its pathogenesis. To date, no study has investigated the association of inflammatory transcription factor, NFκB genes with pterygium in the Middle East. We examined the changes in expression of 3 inflammatory related NFκB1, NFκB2, and RELA genes in patients with pterygium. Thirty patients with pterygium and 30 age and sex-matched controls were enrolled in this case-control study. None of the participants showed any clinical signs of inflammation in their conjunctiva. Demographic information was obtained and the expression levels of three genes including NFκB1, NFκB2, and RELA were measured in their conjunctiva by real-time RT-PCR using gene-specific primers. Mean expression level of NFκB1, NFκB2 and RELA genes in patients were 2.4±0.3, 1.9± 0.5, and 1.8±0.4 times higher than normal subjects, respectively. Higher levels of gene expression were observed in individuals with more outdoor activity and sun exposure. Moreover, a significant correlation was observed between the expression levels of NFκB2 and RELA genes, suggesting a possible NFκB2- RELA heterodimer formation in patients with pterygium. This study has indicated a significant association between expressions of inflammatory-related NFκB1, NFκB2 and RELA genes, and pterygium. Further studies to verify the role of inflammation in the pathogenesis of pterygium, may provide new targets for managing pterygia.

Fecal Microbiota Transplantation Beneficially Regulates Intestinal Mucosal Autophagy and Alleviates Gut Barrier Injury

The gut microbiota plays a crucial role in human and animal health, and its disorder causes multiple diseases. Over the past decade, FMT has gained increasing attention due to the success in treating Clostridium difficile infection (CDI) and inflammatory bowel disease (IBD). Although FMT appears to be effective, how FMT functions in the recipient remains unknown. Whether FMT exerts this beneficial effect through a series of changes in the host organism caused by alteration of gut microbial structure is also not known. In the present study, newborn piglets and E. coli K88-infected piglets were selected as models to explore the interplay between host and gut microbiota following FMT. Our results showed that FMT triggered intestinal mucosal autophagy and alleviated gut barrier injury caused by E. coli K88. This report provides a theoretical basis for the use of FMT as a viable therapeutic method for gut microbial regulation.

Fecal microbiota transplantation (FMT) is one of the most effective ways to regulate the gut microbiota. Here, we investigated the effect of exogenous fecal microbiota on gut function from the perspective of analysis of the mucosal proteomes in a piglet model. A total of 289 differentially expressed proteins were annotated with 4,068 gene ontology (GO) function entries in the intestinal mucosa, and the levels of autophagy-related proteins in the forkhead box O (FoxO) signaling pathway were increased whereas the levels of proteins related to inflammation response were decreased in the recipient. Then, to assess the alleviation of epithelial injury in the Escherichia coli K88-infected piglets following FMT, intestinal microbiome-metabolome responses were determined. 16S rRNA gene sequencing showed that the abundances of beneficial bacteria, such as Lactobacillus and Succinivibrio, were increased whereas those of Enterobacteriaceae and Proteobacteria bacteria were decreased in the infected piglets following FMT. Metabolomic analysis revealed that levels of 58 metabolites, such as lactic acid and succinic acid, were enhanced in the intestinal lumen and that seven metabolic pathways, such as branched-chain amino acid metabolism pathways, were upregulated in the infected piglets following FMT. In concordance with the metabolome data, results of metagenomics prediction analysis also demonstrated that FMT modulated the metabolic functions of gut microbiota associated with linoleic acid metabolism. In addition, intestinal morphology was improved, a result that coincided with the decrease of intestinal permeability and the enhancement of mucins and mucosal expression of tight junction proteins in the recipient. Taken together, the results showed that FMT triggered intestinal mucosal protective autophagy and alleviated gut barrier injury through alteration of the gut microbial structure.

IMPORTANCE The gut microbiota plays a crucial role in human and animal health, and its disorder causes multiple diseases. Over the past decade, FMT has gained increasing attention due to the success in treating Clostridium difficile infection (CDI) and inflammatory bowel disease (IBD). Although FMT appears to be effective, how FMT functions in the recipient remains unknown. Whether FMT exerts this beneficial effect through a series of changes in the host organism caused by alteration of gut microbial structure is also not known. In the present study, newborn piglets and E. coli K88-infected piglets were selected as models to explore the interplay between host and gut microbiota following FMT. Our results showed that FMT triggered intestinal mucosal autophagy and alleviated gut barrier injury caused by E. coli K88. This report provides a theoretical basis for the use of FMT as a viable therapeutic method for gut microbial regulation.

Discovery of Novel Small-Molecule Inhibitors of NF-κB Signaling with Antiinflammatory and Anticancer Properties

Excessive NF-κB activation contributes to the pathogenesis of numerous diseases. Small-molecule inhibitors of NF-κB signaling have significant therapeutic potential especially in treating inflammatory diseases and cancers. In this study, we performed a cell-based high-throughput screening to discover novel agents capable of inhibiting NF-κB signaling. On the basis of two hit scaffolds from the screening, we synthesized 69 derivatives to optimize the potency for inhibition of NF-κB activation, leading to successful discovery of the most potent compound Z9j with over 170-fold enhancement of inhibitory activity. Preliminary mechanistic studies revealed that Z9j inhibited NF-κB signaling via suppression of Src/Syk, PI3K/Akt, and IKK/IκB pathways. This novel compound also demonstrated antiinflammatory and anticancer activities, warranting its further development as a potential multifunctional agent to treat inflammatory diseases and cancers.

Gefitinib Inhibits Bleomycin-Induced Pulmonary Fibrosis via Alleviating the Oxidative Damage in Mice

Pulmonary fibrosis (PF) is a life-threatening interstitial lung disease. In this study, we tried to reveal the model of action between high-mobility group box 1 (HMGB1) and α-smooth muscle actin (α-SMA) and the protective role of gefitinib in pulmonary fibrosis induced by the administration of bleomycin aerosol in mice. For the mechanism study, lung tissues were harvested two weeks after modeling to detect the coexpression of HMGB1 and α-SMA by immunohistochemistry and immunofluorescence staining. Protein-DNA interactions were analyzed using a pulldown assay to study the relationship between HMGB1 and α-SMA. For the gefitinib treatment study, the mice were divided into three groups: phosphate-buffered saline (PBS) control group, PBS-treated PF group, and gefitinib-treated PF group. Gavage of gefitinib or PBS (20 mg/kg/day) was performed after bleomycin treatment for two weeks until the mice were sacrificed. Lung and blood samples were collected to assess the histological changes, oxidative stress, and expression of NOXs, HMGB1, EGFR, MAPKs, AP-1, and NF-κB to determine the curative effect and related molecular mechanisms. The results revealed the high coexpression of α-SMA and HMGB1 in some interstitial cells in the fibrotic lung. The DNA-protein pulldown analysis proved that HMGB34367 acted as a novel transcriptional factor for the α-SMA promoter and participated in the eventual development of pulmonary fibrosis. Second, gefitinib could significantly decrease lung fibrotic changes and the level of MDA and recover the T-AOC level. Meanwhile, gefitinib could also reduce the NOX1/2/4, HMGB1, p-EGFR, p-ERK, p-JNK, p-P38, p-NF-κB, p-c-Jun, and p-c-Fos expression levels in fibrotic lungs. The present study suggested that gefitinib could alleviate lung fibrosis through the HMGB1/NOXs-ROS/EGFR-MAPKs-AP-1/NF-κB signal in bleomycin-induced pulmonary fibrosis.

Lymphotoxin α fine-tunes T cell clonal deletion by regulating thymic entry of antigen-presenting cells

Medullary thymic epithelial cells (mTEC) purge the T cell repertoire of autoreactive thymocytes. Although dendritic cells (DC) reinforce this process by transporting innocuous peripheral self-antigens, the mechanisms that control their thymic entry remain unclear. Here we show that mTEC-CD4+ thymocyte crosstalk regulates the thymus homing of SHPS-1+ conventional DCs (cDC), plasmacytoid DCs (pDC) and macrophages. This homing process is controlled by lymphotoxin α (LTα), which negatively regulates CCL2, CCL8 and CCL12 chemokines in mTECs. Consequently, Ltα-deficient mice have increased expression of these chemokines that correlates with augmented classical NF-κB subunits and increased thymic recruitment of cDCs, pDCs and macrophages. This enhanced migration depends mainly on the chemokine receptor CCR2, and increases thymic clonal deletion. Altogether, this study identifies a fine-tuning mechanism of T cell repertoire selection and paves the way for therapeutic interventions to treat autoimmune disorders.

Mechanisms of Phytonutrient Modulation of Cyclooxygenase-2 (COX-2) and Inflammation Related to Cancer

The link between chronic inflammation and cancer involves cytokines and mediators of inflammatory pathways. Cyclooxygenase-2 (COX-2), a key enzyme in fatty acid metabolism, is upregulated during both inflammation and cancer. COX-2 is induced by pro-inflammatory cytokines at the site of inflammation and enhanced COX-2-induced synthesis of prostaglandins stimulates cancer cell proliferation, promotes angiogenesis, inhibits apoptosis, and increases metastatic potential. As a result, COX-2 inhibitors are a subject of intense research interest toward potential clinical applications. Epidemiological studies highlight the potential benefits of diets rich in phytonutrients for cancer prevention. Plants contain numerous phytonutrient secondary metabolites shown to modulate COX-2. Studies have shown that these metabolites, some of which are used in traditional medicine, can reduce inflammation and carcinogenesis. This review describes the molecular mechanisms by which phytonutrients modulate inflammation, including studies of carotenoids, phenolic compounds, and fatty acids targeting various inflammation-related molecules and pathways associated with cancer. Examples of pathways include those of COX-2, mitogen-activated protein kinase kinase kinase, mitogen-activated protein kinase, pro-inflammatory cytokines, and transcription factors like nuclear factor kappa B. Such phytonutrient modulation of COX-2 and inflammation continue to be explored for applications in the prevention and treatment of cancer.

Regulation of T-Cell Signaling by Post-Translational Modifications in Autoimmune Disease

The adaptive immune system involves antigen-specific host defense mechanisms mediated by T and B cells. In particular, CD4⁺ T cells play a central role in the elimination of pathogens. Immunological tolerance in the thymus regulates T lymphocytes to avoid self-components, including induction of cell death in immature T cells expressing the self-reactive T-cell receptor repertoire. In the periphery, mature T cells are also regulated by tolerance, e.g., via induction of anergy or regulatory T cells. Thus, T cells strictly control intrinsic signal transduction to prevent excessive responses or self-reactions. If the inhibitory effects of T cells on these mechanisms are disrupted, T cells may incorrectly attack self-components, which can lead to autoimmune disease. The functions of T cells are supported by post-translational modifications, particularly phosphorylation, of signaling molecules, the proper regulation of which is controlled by endogenous mechanisms within the T cells themselves. In recent years, molecular targeted agents against kinases have been developed for treatment of autoimmune diseases. In this review, we discuss T-cell signal transduction in autoimmune disease and provide an overview of acetylation-mediated regulation of T-cell signaling pathways.

Kaempferol 7-O-β-D-glucoside isolated from the leaves of Cudrania tricuspidata inhibits LPS-induced expression of pro-inflammatory mediators through inactivation of NF-κB, AP-1, and JAK-STAT in RAW 264.7 macrophages

Kaempferol 7-O-β-D-glucoside (KPG), a natural flavonol isolated from Cudrania tricuspidata, has been reported to exert anti-cancer effects; however, its anti-inflammatory effects have not yet been reported. In this study, we demonstrate the suppressive effect of KPG on the production of nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages and mouse bone marrow-derived macrophages. KPG downregulated the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level and iNOS, COX-2, TNF-α, IL-1β, and IL-6 at the mRNA level in LPS-treated RAW 264.7 macrophages. Moreover, we elucidated the underlying molecular mechanism, demonstrating that KPG attenuated LPS-induced nuclear factor-κB (NF-κB) activation by decreasing p65 nuclear translocation, inhibiting κBα (IκBα) phosphorylation/degradation and IκB kinaseα/β (IKKα/β) phosphorylation. KPG additionally reduced LPS-induced activator protein-1 (AP-1) activity by inhibiting c-Fos expression in the nucleus, though c-Jun was not affected. Furthermore, we revealed that KPG significantly abrogated the LPS-induced phosphorylation of signal transducer and activator of transcription (STAT) 1 (Ser 727, Tyr 701) and STAT3 (Tyr 705) through inhibiting the phosphorylation of Janus kinase (JAK) 1 and JAK2, its upstream activating proteins. Taken together, our data suggest that KPG induces anti-inflammatory activity by blocking NF-κB, AP-1, and JAK-STAT signaling pathways in LPS-treated RAW 264.7 macrophages, thus suppressing inflammatory mediators.

Protective role of tenuigenin on sepsis-induced acute kidney injury in mice

Acute kidney injury (AKI) is a severe complication of sepsis, which largely contributes to the associated high mortality rate. Tenuigenin (TNG) is a natural product isolated from Polygala tenuifolia root, which possesses anti-inflammatory and anti-oxidant properties. The present study investigated the effects of TNG on sepsis-associated AKI in mice subjected to cecal ligation and puncture (CLP). TNG was demonstrated to alleviate sepsis-induced AKI by reducing pathological changes and significantly decreasing the levels of blood urea nitrogen, serum creatinine and kidney coefficient. The production of inflammatory cytokines, including tumor necrosis factor α and interleukin-6, was markedly inhibited by TNG. Hematoxylin-eosin staining revealed that the morphological changes of kidney tissues in CLP mice were reversed following TNG treatment. Furthermore, treatment with TNG inhibited the production of nitric oxide and prostaglandin E₂. Finally, TNG inhibited the activation of the nuclear factor-κB (NF-κB) signaling pathway. The present study suggested that TNG alleviates sepsis-induced AKI by inhibiting the NF-κB signaling pathway, which provides a novel approach for treating sepsis-induced AKI.

Protein extracted from Porphyra yezoensis prevents cisplatin-induced nephrotoxicity by downregulating the MAPK and NF-κB pathways

Acute renal failure is a serious complication of treatment with the anticancer drug cisplatin. Cisplatin exerts a cytotoxic effect on renal cells by inducing apoptosis through activating the tumor suppressor p53, nuclear factor‑κB (NF‑κB) and mitogen‑activated protein kinase (MAPK)/p38 pathways. Effects of protein extracts of the brown seaweed Porphyra yezoensis (P. yezoensis) on cytotoxicity, inflammation and cell proliferation have been reported; however, the effects of P. yezoensis protein (PYP) extract on cisplatin‑induced renal injury have remained elusive. The present study investigated the effects of PYP on cisplatin‑induced nephrotoxicity in the HK2 human proximal tubular epithelial cell line. PYP treatment reduced cisplatin‑induced apoptosis and death of HK2 cells by restoring the B‑cell lymphoma‑2 (Bcl‑2)‑associated X protein (Bax)/Bcl‑2 imbalance, cytochrome c release and caspase‑3 activation. In addition, PYP activated the redox‑sensitive transcription factor NF‑κB via stimulating the nuclear translocation of p65 in HK2 cells. PYP also restored renal antioxidant levels and increased the total and nuclear accumulation of NF erythroid 2‑related factor 2 in HK2 cells. PYP markedly attenuated cisplatin‑induced p38, MAPK and c‑Jun N‑terminal kinase phosphorylation. Furthermore, treatment with PYP ameliorated cisplatin‑induced renal cell damage by upregulating antioxidant defense mechanisms and downregulating the MAPK and NF‑κB signaling pathways. In addition, mice were divided into three treatment groups (control, cisplatin and PYP + cisplatin) and the effects of PYP were evaluated in a mouse model of cisplatin‑induced acute kidney injury. The concentrations of blood urea nitrogen and serum creatinine in the PYP + cisplatin group were lower than those in the cisplatin group. The mRNA expression levels of inflammatory factors interleukin‑6 (IL‑6), IL‑1β, tumor necrosis factor‑α and monocyte chemoattractant protein‑1 in the kidney tissues of the PYP + cisplatin group were also lower than those in the cisplatin group. These results suggest that PYP treatment had a preventive effect on nephrotoxicity, specifically by downregulating the MAPK and NF‑κB signaling pathways and the mRNA levels of inflammatory genes.

Oral subchronic exposure to silver nanoparticles causes renal damage through apoptotic impairment and necrotic cell death

Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials. Following oral exposure, AgNPs can accumulate in various organs including kidneys where they show gender specific accumulation. There is limited information on their effect on renal system following long-term animal exposure especially at the ultramicroscopic and molecular level. In this study, we have assessed the effect of 60 days oral AgNPs treatment on kidneys of female Wistar rats at doses of 50 ppm and 200 ppm that are below previously reported lowest observed adverse effect level (LOAEL). AgNPs treatment led to decrease in kidney weight and some loss of renal function as seen by increased levels of serum creatinine and early toxicity markers such as KIM-1, clusterin and osteopontin. We also observed significant mitochondrial damage, loss of brush border membranes, pronounced swelling of podocytes and degeneration of their foot processes using transmission electron microscopy (TEM). These symptoms are similar to those seen in nephrotic syndrome and 'Minimal change disease' of kidney where few changes are visible under light microscopy but significant ultrastructural damage is observed. Prolonged treatment of AgNPs also led to the activation of cell proliferative, survival and proinflammatory factors (Akt/mTOR, JNK/Stat and Erk/NF-κB pathways and IL1β, MIP2, IFN-γ, TNF-α and RANTES) and dysfunction of normal apoptotic pathway. Our study shows how long term AgNPs exposure may promote ultrastructural damage to kidney causing inflammation and expression of cell survival factors. These changes, in the long term, could lead to inhibition of the beneficial apoptotic pathway and promotion of necrotic cell death in kidneys.

Absolute Ligand Discrimination by Dimeric Signaling Receptors

Many signaling pathways act through shared components, where different ligand molecules bind the same receptors or activate overlapping sets of response regulators downstream. Nevertheless, different ligands acting through cross-wired pathways often lead to different outcomes in terms of the target cell behavior and function. Although a number of mechanisms have been proposed, it still largely remains unclear how cells can reliably discriminate different molecular ligands under such circumstances. Here we show that signaling via ligand-induced receptor dimerization-a very common motif in cellular signaling-naturally incorporates a mechanism for the discrimination of ligands acting through the same receptor.

Identification and application of anti-inflammatory compounds screening system based on RAW264.7 cells stably expressing NF-κB-dependent SEAP reporter gene

BACKGROUND

NF-κB is one of the key transcription factors in the inflammatory response, transactivates a series of pro-inflammatory genes and is therefore regarded as an important target for anti-inflammatory drug screening.

METHOD

We recombined the reporter gene vector with inserting the "neo" transcript into the vector pNF-κB-SEAP, made the reporter gene vector stable in a eukaryotic cell line. The recombinant reporter gene vector we named pNF-κB-SEAP-Neo was transfected into RAW264.7. We selected the transfected RAW264.7 cell line with G418 for 15 days and then get RAW264.7 cells stably expressing NF-κB-dependent SEAP named as RAW264.7-pNF-κB-SEAP cells. We treated the RAW264.7-pNF-κB-SEAP cells with NF-κB agonists as LPS, PolyI:C and TNF-α, NF-κB inhibitor as PDTC and BAY117085, in different concentrations and time points and tested the expression of the SEAP, constructed the drug screening system on the base of the RAW264.7-pNF-κB-SEAP cell line. 130 chemicals were screened with the drug screening system we constructed and one of these chemicals numbered w10 was found could inhibit the NF-κB significantly. At last, we verified the inhibition of w10 to expression of genes promoted with NF-κB in HepG2 and Hela, and to migration of Hela.

RESULT

In this study, we established a drug screening system based on RAW264.7 cells that stably expressed the NF-κB-dependent, SEAP reporter gene. To develop a standard method for drug screening using this reporter-gene cell line, the test approach of SEAP was optimized and basic conditions for drug screening were chosen. This included the initial cell number inoculated in a 96-well plate, the optimum agonist, inhibitor of NF-κB pathway and their concentrations during screening. Subsequently, 130 newly synthesized compounds were screened using the stable reporter-gene cell line. The anti-inflammatory effects of the candidate compounds obtained were further verified in 2 cancer cell lines. The results indicated that compound W10 (methyl 4-(4-(prop-2-yn-1-ylcarbamoyl) phenylcarbamoyl) benzoate) significantly inhibited SEAP production under the screening conditions. Further results confirmed that the precursor compound significantly inhibited the transcription of NF-κB target genes.

CONCLUSION

In conclusion, RAW264.7 cells, stably expressing the NF-κB-dependent SEAP-reporter gene, may provide a new, feasible, and efficient cellular drug-screening system.

Non-canonical NFκB mutations reinforce pro-survival TNF response in multiple myeloma through an autoregulatory RelB:p50 NFκB pathway

Environmental drug resistance constitutes a serious impediment for therapeutic intervention in multiple myeloma. Tumor-promoting cytokines, such as tumor necrosis factor (TNF), induce nuclear factor-κB (NFκB)- driven expression of pro-survival factors, which confer resistance in myeloma cells to apoptotic insults from TNF-related apoptosis-inducing ligand (TRAIL) and other chemotherapeutic drugs. It is thought that RelA:p50 dimer, activated from IκBα-inhibited complex in response to TNF-induced canonical NFκB signal, mediates the pro-survival NFκB function in cancerous cells. Myeloma cells additionally acquire gain-of-function mutations in the non-canonical NFκB module, which induces partial proteolysis of p100 into p52 to promote RelB:p52/NFκB activation from p100-inhibited complex during immune cell differentiation. However, role of non-canonical NFκB signaling in the drug resistance in multiple myeloma remains unclear. Here we report that myeloma-associated non-canonical aberrations reinforce pro-survival TNF signaling in producing a protracted TRAIL-refractory state. These mutations did not act through a typical p52 NFκB complex, but completely degraded p100 to reposition RelB under IκBα control, whose degradation during TNF signaling induced an early RelB:p50 containing NFκB activity. More so, autoregulatory RelB synthesis prolonged this TNF-induced RelB:p50 activity in myeloma cells harboring non-canonical mutations. Intriguingly, TNF-activated RelB:p50 dimer was both necessary and sufficient, and RelA was not required, for NFκB-dependent pro-survival gene expressions and suppression of apoptosis. Indeed, high RelB mRNA expressions in myeloma patients correlated with the augmented level of pro-survival factors and resistance to therapeutic intervention. In sum, we provide evidence that cancer-associated mutations perpetuate TNF-induced pro-survival NFκB activity through autoregulatory RelB control and thereby exacerbate environmental drug resistance in multiple myeloma.

Increased βTrCP are associated with imiquimod-induced psoriasis-like skin inflammation in mice via NF-κB signaling pathway

Psoriasis is a common inflammatory skin disease characterized by T cell-mediated hyperproliferation of keratinocytes, increased angiogenesis and inflammation. Accumulating evidence suggests that some keratinocyte differentiation events are controlled by the ubiquitin/proteasome system. β-transducin repeat-containing protein (βTrCP) serve as substrate recognition component of E3 ubiquitin ligases that control stability of important regulators of signal transduction including the nuclear factor (NF)-κB signaling, a key regulatory element in inflammatory pathways related to psoriasis, suggesting a potential role of βTrCP in psoriasis pathogenesis. However, no published study has investigated the role of βTrCP in the etiology of psoriasis. Here, we combined an in vitro cell model of tumor necrosis factor (TNF)-α-induced keratinocyte inflammation and an animal model of imiquimod (IMQ)-induced psoriasis-like inflammation to investigate the pathogenic mechanisms in psoriasis-like dermatitis and assess its βTrCP/NF-κB dependency. Daily application of IMQ on mouse back skin induced inflamed scaly skin lesions resembling plaque type psoriasis. These lesions were associated with elevated βTrCP levels, reduced inhibitor κB (IκB), and enhanced NF-κB activation in epidermal tissues. Furthermore, βTrCP knockdown via siRNA in in TNF-α-stimulated HaCaT and normal human epidermal keratinocytes (NHEK) cells significantly inhibited the over-activation of NF-κB and expression of intercellular adhesion molecule 1 (ICAM-1), demonstrating a pivotal role of βTrCP in regulation the TNF-α-activated NF-κB inflammatory pathways. Moreover, downregulation of βTrCP through lentiviral shRNA ameliorates IMQ-induced psoriasis-like skin lesions in vivo. In conclusion, βTrCP is involved in the NF-κB signaling mediated-, psoriasis-related inflammation and represent a novel target for developing agents to treat psoriasis.

Repeated lipopolysaccharide exposure causes corticosteroid insensitive airway inflammation via activation of phosphoinositide-3-kinase δ pathway

Corticosteroid resistance is one of major barriers to effective management of chronic inflammatory respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and severe asthma. These patients often experience exacerbations with viral and/or bacterial infection, which may cause continuous corticosteroid insensitive inflammation. In this study, we observed that repeated exposure of lipopolysaccharide (LPS) intranasally attenuated the anti-inflammatory effects of the corticosteroid fluticasone propionate (FP) on neutrophils and CXCL1 levels in bronchoalveolar lavage (BAL) fluid in an in vivo murine model. Histone deacetylase-2 (HDAC2) and NF-E2 related factor 2 (Nrf2) levels in lungs after LPS administration for 3 consecutive days were significantly decreased to 38.9±6.3% (mean±SEM) and 77.5±2.7% of the levels seen after only one day of LPS exposure, respectively. In addition, 3 days LPS exposure resulted in an increase of Akt phosphorylation, indicating activation of the phosphoinositide-3-kinase (PI3K) pathway by 4-fold in lungs compared with 1 day of exposure. Furthermore, combination treatment with theophylline and FP significantly decreased the neutrophil accumulation and CXCL1 concentrations in BAL fluid from 22.5±1.8×10⁴ cells/mL and 214.6±20.6 pg/mL to 7.9±0.5×10⁴ cells/mL and 61.9±13.3 pg/mL, respectively. Combination treatment with IC87114, a selective PI3Kδ inhibitor, and FP also significantly decreased neutrophils and CXCL1 levels from 16.8±0.7×10⁴ cells/mL and 182.4±4.6 pg/mL to 5.9±0.3×10⁴ cells/mL and 71.4±2.7 pg/mL, respectively. Taken together, repeated exposure of LPS causes corticosteroid-insensitive airway inflammation in vivo, and the corticosteroid-resistance induced by LPS is at least partly mediated through the activation of PI3Kδ, resulting in decreased levels of HDAC2 and Nrf2. These findings provide a potentially new therapeutic approach to COPD and severe asthma.

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We first time proposed clinically relevant steroid insensitive exacerbation model.

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LPS caused corticosteroid insensitive airway inflammation via PI3Kδ activation.

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This murine model are useful to discover new therapies for airway inflammation.

How Mouse Macrophages Sense What Is Going On

Macrophages are central to both innate and adaptive immunity. With few exceptions, macrophages are the first cells that sense trouble and respond to disturbances in almost all tissues and organs. They sense their environment, inhibit or kill pathogens, take up apoptotic and necrotic cells, heal tissue damage, and present antigens to T cells. Although the origins (yolk sac versus monocyte-derived) and phenotypes (functions, gene expression profiles, surface markers) of macrophages vary between tissues, they have many receptors in common that are specific to one or a few molecular species. Here, we review the expression and function of almost 200 key macrophage receptors that help the macrophages sense what is going on, including pathogen-derived molecules, the state of the surrounding tissue cells, apoptotic and necrotic cell death, antibodies and immune complexes, altered self molecules, extracellular matrix components, and cytokines, including chemokines.

Vitamin D attenuates inflammation in CFTR knockdown intestinal epithelial cells but has no effect in cells with intact CFTR

The cystic fibrosis (CF) intestine is characterized by chronic inflammation. CF patients are instructed to ingest supplemental vitamin D on a daily basis thereby exposing their intestinal tract to pharmacological amounts of this vitamin. It has been shown that vitamin D exerts intestinal anti-inflammatory properties. We therefore postulate that vitamin D may be beneficial in the management of CF intestinal inflammation by attenuating cellular inflammatory responses. In this study, we investigated the anti-inflammatory effects of the oral form of vitamin D3 (cholecalciferol) and its metabolites, 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3, on cytokine-induced inflammatory responses in intestinal epithelial Caco-2/15 cells with intact expression of CF transmembrane conductance regulator (CFTR) and knockdown for CFTR. We show that 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 inhibited p38MAPK phosphorylation and that these effects were not mediated by changes in the expression of MAPK phosphatase-1 (MKP-1). However, 1,25-dihydroxyvitamin D3 exhibited superior anti-inflammatory effects as it furthermore reduced cytokine-induced NF-κB nuclear translocation and interleukin-8 mRNA stability and secretion. Intriguingly, the anti-inflammatory effects of vitamin D metabolites were only observed in CFTR knockdown cells, which may be explained by alterations in its catabolism associated with changes in CYP24A1 expression. These observations were supported in vivo whereby Cftr(-/-) mice fed large amounts of vitamin D3 for 2 mo led to a reduction in the number of eosinophils and apoptotic cells in the duodenal mucosa of females but not males. Altogether, these findings suggest that vitamin D exerts intestinal anti-inflammatory actions under specific circumstances and may thus prove beneficial in CF.