Hierarchies of NF-κB target-gene regulation

Serum Metabolomics and NF-κB Pathway Analysis Revealed the Antipyretic Mechanism of Ellagic Acid on LPS-Induced Fever in Rabbits

Fever is one of the most common clinical conditions and is characterized by pyrogenic infection, malignancy, inflammation, and tissue damage, among others. Ellagic acid (EA) can inhibit the expression of related proteins on the pathway by blocking the nuclear factor kappa-B(NF-κB) signaling pathway, inhibit the levels of pro-inflammatory factors interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α), increase the level of anti-inflammatory factor IL-10, and effectively alleviate inflammatory symptoms. In addition, EA can also reduce the levels of malondialdehyde(MDA) and nitric oxide(NO) in the body, increase the activities of superoxide dismutase (SOD), glutathione (GSH), and catalase(CAT), scavenge oxidative free radicals, inhibit lipid oxidation, and achieve antipyretic and anti-inflammatory effects. The purpose of this study was to establish the relationship between EA and various inflammatory markers, such as TNF-α, IL-6, IL-1β, prostaglandin E2(PGE2), and cyclic adenosine monophosphate(cAMP), and clarify the mechanism of the cyclooxidase-2(COX-2)/NF-κB signaling pathway. Combined with the metabolomics analysis, our study revealed the effects of EA on multiple endogenous biomarkers, reflecting the characteristics of a multi-component, multi-target, and multi-pathway mechanism. Compared to lipopolysaccharide (LPS)- treated animals, subsequent administration of EA significantly lowered the LPS-induced rectal temperature increase (p < 0.05 or p < 0.01), significantly increased serum SOD and GSH levels (p < 0.05 or p < 0.01), and significantly decreased serum MDA, IL-1β, IL-6, and TNF-α levels (p < 0.05 or p < 0.01). In addition, compared to LPS-treated animals, subsequent administration of EA significantly decreased cerebrospinal fluid cAMP and PGE2 levels (p < 0.05 or p < 0.01), significantly decreased cAMP, significantly increased 5-HT levels (p < 0.05 or p < 0.01), and significantly down-regulated p-NF-κB p65 and COX-2 protein levels in the hypothalamus. Subsequent gas chromatography mass spectrometry(GC-MS) metabolite analysis indicated that 12 differential metabolites were detected in serum isolated 4 h after LPS treatment, and 10 differential metabolites were detected in serum collected 7 h after LPS treatment. Next, Pearson correlation analysis was used to systematically characterize the relationship between the identified metabolites and TNF-α, IL-6, MDA, SOD, PGE2, and cAMP. The levels of propionic acid, pyridine, and L-valine were up-regulated by EA, which inhibited the expression of MDA, IL-1β, and TNF-α and increased the activity of GSH. The levels of inositol, urea, and 2-monopalmitin were down-regulated by EA, which inhibited the expression of MDA, IL-1β, and TNF-α, increased the activity of SOD and GSH, reduced the inflammatory response, and alleviated the oxidative stress state. Combined with the results of the metabolic pathway analysis, we suggest that the pathways of the galactose metabolism, synthesis and degradation of ketone bodies, as well as ascorbic acid and aldehyde acid metabolism are closely related to the antipyretic and anti-inflammatory effects of EA. Our study established the relationship between EA and various inflammatory markers, such as TNF-α, IL-6, IL-1β, PGE2, and cAMP, and clarified the mechanism of the COX-2/NF-κB signaling pathway. Combined with the metabolomics analysis, our study revealed the effects of EA on multiple endogenous biomarkers, reflecting the characteristics of a multi-component, multi-target, and multi-pathway mechanism.

Type 1 diabetes impairs the activity of rat testicular somatic and germ cells through NRF2/NLRP3 pathway-mediated oxidative stress

Background

It is well known that metabolic disorders, including type 1 diabetes (T1D), are often associated with reduced male fertility, mainly increasing oxidative stress and impairing the hypothalamus-pituitary-testis (HPT) axis, with consequently altered spermatogenesis and reduced sperm parameters. Herein, using a rat model of T1D obtained by treatment with streptozotocin (STZ), we analyzed several parameters of testicular activity.

Methods

A total of 10 adult male Wistar rats were divided into two groups of five: control and T1D, obtained with a single intraperitoneal injection of STZ. After 3 months, the rats were anesthetized and sacrificed; one testis was stored at -80°C for biochemical analysis, and the other was fixed for histological and immunofluorescence analysis.

Results

The data confirmed that T1D induced oxidative stress and, consequently, alterations in both testicular somatic and germ cells. This aspect was highlighted by enhanced apoptosis, altered steroidogenesis and Leydig cell maturity, and impaired spermatogenesis. In addition, the blood-testis barrier integrity was compromised, as shown by the reduced levels of structural proteins (N-cadherin, ZO-1, occludin, connexin 43, and VANGL2) and the phosphorylation status of regulative kinases (Src and FAK). Mechanistically, the dysregulation of the SIRT1/NRF2/MAPKs signaling pathways was proven, particularly the reduced nuclear translocation of NRF2, affecting its ability to induce the transcription of genes encoding for antioxidant enzymes. Finally, the stimulation of testicular inflammation and pyroptosis was also confirmed, as highlighted by the increased levels of some markers, such as NF-κB and NLRP3.

Conclusion

The combined data allowed us to confirm that T1D has detrimental effects on rat testicular activity. Moreover, a better comprehension of the molecular mechanisms underlying the association between metabolic disorders and male fertility could help to identify novel targets to prevent and treat fertility disorders related to T1D.

Isobavachalcone attenuates liver fibrosis via activation of the Nrf2/HO-1 pathway in rats

Liver fibrosis, a progression of chronic liver disease, is a significant concern worldwide due to the lack of effective treatment modalities. Recent studies have shown that natural products play a crucial role in preventing and treating liver fibrosis. Isobavachalcone (IBC) is a chalcone compound with anti-inflammatory, antioxidant, and anti-cancer properties. However, its potential antifibrotic effects remain to be elucidated. This study aimed to investigate the antifibrotic effects of IBC on liver fibrosis and its underlying mechanisms in rats. The results showed that IBC significantly ameliorated the pathological damage and collagen deposition in liver tissues; it also reduced the levels of hydroxyproline (HYP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). In addition, IBC activated Nuclear factor E2-associated factor 2/Hemeoxygenase-1 (Nrf2/HO-1) signaling, leading to the nuclear translocation of Nrf2. This translocation subsequently increased the levels of superoxide dismutase (SOD) and glutathione (GSH) and decreased the levels of malondialdehyde (MDA) and reactive oxygen species (ROS), thereby alleviating oxidative stress-induced damage. Moreover, it inhibited the expression of nuclear factor kappa B (NF-κB), which further reduced the levels of downstream inflammatory factors, such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1 beta (IL-1β), thereby suppressing the activation of HSCs and weakening liver fibrosis. In HSC-T6 cell experiments, changes observed in inflammatory responses, oxidative stress indicators, and protein expression were consistent with the in vivo results. Furthermore, the Nrf2 inhibitor (ML385) attenuated the effect of IBC on inhibiting the activation of quiescent HSCs. Consequently, IBC could alleviate liver fibrosis by activating Nrf2/ HO-1 signaling.

Sirtuins in macrophage immune metabolism: A novel target for cardiovascular disorders

Sirtuins (SIRT1-SIRT7), as a family of NAD+-dependent protein modifying enzymes, have various catalytic functions, such as deacetylases, dealkalylases, and deribonucleases. The Sirtuins family is directly or indirectly involved in pathophysiological processes such as glucolipid metabolism, oxidative stress, DNA repair and inflammatory response through various pathways and assumes an important role in several cardiovascular diseases such as atherosclerosis, myocardial infarction, hypertension and heart failure. A growing number of studies supports that metabolic and bioenergetic reprogramming directs the sequential process of inflammation. Failure of homeostatic restoration leads to many inflammatory diseases, and that macrophages are the central cells involving the inflammatory response and are the main source of inflammatory cytokines. Regulation of cellular metabolism has emerged as a fundamental process controlling macrophage function, but its exact signaling mechanisms remain to be revealed. Understanding the precise molecular basis of metabolic control of macrophage inflammatory processes may provide new approaches for targeting immune metabolism and inflammation. Here, we provide an update of studies in cardiovascular disease on the function and role of sirtuins in macrophage inflammation and metabolism, as well as drug candidates that may interfere with sirtuins, pointing to future prospects in this field.

Prostaglandin D2 regulates Escherichia coli-induced inflammatory responses through TLR2, TLR4, and NLRP3 in macrophages

Prostaglandin D2 (PGD2) synthesis is closely associated with the innate immune response mediated by pattern recognition receptors (PPRs). We determined PGD2 synthesis whether mediated by Toll-like receptor 2 (TLR2), TLR4 and Nod-like receptor pyrin domain-containing protein 3 (NLRP3) in Escherichia coli (E. coli)-, lipopolysaccharide (LPS)- and Braun lipoprotein (BLP)-stimulated macrophages. Our data demonstrate that TLR2, TLR4, and NLRP3 could regulate the synthesis of PGD2 through cyclo-oxygenase-2 (COX-2) and hematopoietic PGD synthase (H-PGDS) in E. coli-, LPS- or BLP-stimulated macrophages, suggesting that TLR2, TLR4, and NLRP3 are critical in regulating PGD2 secretion by controlling PGD2 synthetase expression in E. coli-, LPS- or BLP-stimulated macrophages. The H-PGDS (a PGD2 specific synthase) inhibitor pre-treatment could down-regulate the secretion of TNF-α, RANTES and IL-10 in LPS- and E. coli-stimulated macrophage. Meanwhile, H-PGDS inhibitor could down-regulate the secretion of TNF-α, while up-regulated RANTES and IL-10 secretion in BLP-stimulated macrophages, suggesting that PGD2 could regulate the secretion of cytokines and chemokines in E. coli-, LPS- or BLP-stimulated macrophages. Furthermore, exogenous PGD2 regulates the secretion of cytokines and chemokines through activation of MAPK and NF-κB signaling pathways after E. coli-, LPS- or BLP stimulation in macrophages. Taken together, PGD2 is found able to regulate E. coli-induced inflammatory responses through TLR2, TLR4, and NLRP3 in macrophages.

Transcutaneous Immunotherapy for RNAi: A Cascade-Responsive Decomposable Nanocomplex Based on Polyphenol-Mediated Framework Nucleic Acid in Psoriasis

Skin is the first barrier against external threats, and skin immune dysfunction leads to multiple diseases. Psoriasis is an inflammatory, chronic, common, immune-related skin disease that affects more than 125 million people worldwide. RNA interference (RNAi) therapy is superior to traditional therapies, but rapid degradation and poor cell uptake are the greatest obstacles to its clinical transformation. The transdermal delivery of siRNA and controllable assembly/disassembly of nanodrug delivery systems can maximize the therapeutic effect. Tetrahedral framework nucleic acid (tFNA) is undoubtedly the best carrier for the transdermal transport of genes due to its excellent noninvasive transdermal effect and editability. The authors combine acid-responsive tannic acid (TA), RNase H-responsive sequences, siRNA, and tFNA into a novel transdermal RNAi drug with controllable assembly and disassembly: STT. STT has heightened resistance to enzyme, serum, and lysosomal degradation, and its size is similar to that of tFNA, enabling easy transdermal transport. After transdermal administration, STT can specifically silence nuclear factor kappa-B (NF-κB) p65, thereby maintaining the stability of the skin's microenvironment and reshaping normal skin immune defense. This work demonstrates the advantages of STT in RNAi therapy and the potential for future treatment of skin-related diseases.

Inducible nitric oxide synthase activity mediates TNF-α-induced endothelial cell dysfunction

Inducible nitric oxide synthase (iNOS) and vascular endothelial dysfunction have been implicated in the development and progression of atherosclerosis. This study aimed to elucidate the role of iNOS in vascular endothelial dysfunction. Ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry combined with multivariate data analysis was used to characterize the metabolic changes in human umbilical vein endothelial cells (HUVECs) in response to different treatment conditions. In addition, molecular biology techniques were employed to explain the molecular mechanisms underlying the role of iNOS in vascular endothelial dysfunction. Tumor necrosis factor-α (TNF-α) enhances the expression of iNOS, TXNIP, and the level of reactive oxygen species (ROS) facilitates the entry of nuclear factor-κB (NF-κB) into the nucleus and promotes injury in HUVECs. iNOS deficiency reversed the TNF-α-mediated pathological changes in HUVECs. Moreover, TNF-α increased the expression of tumor necrosis factor receptor-2 (TNFR-2) and the levels of p-IκBα and IL-6 proteins and CD31, ICAM-1, and VCAM-1 protein expression, which was significantly reduced in HUVECs with iNOS deficiency. In addition, treating HUVECs in the absence or presence of TNF-α or iNOS, respectively, enabled the identification of putative endogenous biomarkers associated with endothelial dysfunction. These biomarkers were involved in critical metabolic pathways, including glycosylphosphatidylinositol-anchor biosynthesis, amino acid metabolism, sphingolipid metabolism, and fatty acid metabolism. iNOS deficiency during vascular endothelial dysfunction may affect the expression of TNFR-2, vascular adhesion factors, and the level of ROS via cellular metabolic changes, thereby attenuating vascular endothelial dysfunction.NEW & NOTEWORTHY Inducible nitric oxide synthase (iNOS) deficiency during vascular endothelial dysfunction may affect the expression of tumor necrosis factor receptor-2 and vascular adhesion factors via cellular metabolic changes, thereby attenuating vascular endothelial dysfunction.

Evaluating the Antioxidant Properties of the Ancient-Crop Tef (Eragrostis tef) Grain Extracts in THP-1 Monocytes

Tef (Eragrostis tef) is an orphan crop that is widely grown in East Africa, primarily in Ethiopia as a staple crop. It is becoming popular in the Western world owing to its nutritious and gluten-free grains and the forage quality of its biomass. Tef is also considered to have a high antioxidant capacity based on cell-free studies. However, the antioxidant activity of tef has never been validated using a physiologically relevant cell model. The purpose of this study was to investigate the antioxidant capacity of tef grain extracts using a mammalian cell model. We hypothesized that the tef grain extracts are capable of modulating the cellular antioxidant response via the modulation of glutathione (GSH) biosynthetic pathways. Therefore, we evaluated the antioxidant activity of purified tef grain extracts in the human acute monocytic leukemia (THP-1) cell line. Our findings revealed that the organic fraction of grain extracts increased the cellular GSH level, which was more evident for brown-colored tef than the ivory variety. Moreover, a brown-tef fraction increased the expressions of GSH-pathway genes, including γ-glutamate cysteine ligase catalytic (GCLC) and modifier (GCLM) subunits and glutathione reductase (GR), an enzyme that plays a key role in GSH biosynthesis, suggesting that tef extracts may modulate GSH metabolism. Several compounds were uniquely identified via mass spectrometry (MS) in GSH-modulating brown-tef samples, including 4-oxo-β-apo-13-carotenone, γ-linolenic acid (methyl ester), 4,4'-(2,3-dimethyl-1,4-butanediyl)bis-phenol (also referred to as 8,8'-lignan-4,4'-diol), and (3β)-3-[[2-[4-(Acetylamino)phenoxy]acetyl]oxy]olean-12-en-28-oic acid. Tef possesses antioxidant activity due to the presence of phytochemicals that can act as direct antioxidants, as well as modulators of antioxidant-response genes, indicating its potential role in alleviating diseases triggered by oxidative stresses. To the best of our knowledge, this is the first report revealing the antioxidant ability of tef extracts in a physiologically relevant human cell model.

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.

Eugenol alleviates Salmonella Typhimurium-infected cecal injury by modulating cecal flora and tight junctions accompanied by suppressing inflammation

BACKGROUND

Salmonella enterica serovar Typhimurium (ST) mainly exists in poultry and poultry related products, which are common sources of human salmonellosis. So, ST is an important zoonotic pathogen that threatens public health and safety. Eugenol has been noted for its antibacterial and anti-inflammatory properties, and it is expected to develop into an antibacterial therapy in vivo.

METHODS

Herein, the effects of eugenol against ST infection in terms of intestinal flora, cecal tight junction, and cecal inflammation in broilers was evaluated in this study.

RESULTS

The results showed that oral eugenol pretreatment obviously relieved the histopathological changes and ultrastructural injury of cecum caused by ST infection. Further analysis found that eugenol lessened the number of ST in the cecum, restrained Proteobacteria and Ruminococcus, and kept the ratio of Firmicutes to Bacteroidetes (F/B), improved the relative abundance of Alistipes compared to the infection control. Moreover, eugenol sustained the expression of ZO-1, claudin-1, and occluding tight junction proteins, reduced the mRNA levels of myeloid differentiation factor 88 (MyD88), toll-like receptor-4 (TLR4) and inducible nitric oxide synthesis (iNOS), suppressed the phosphorylation of p65 and IκBα in the NF-κB signaling pathway, as well as the mRNA levels of TNF-α, IL-1β, IL-2, and IL-18 in the cecum tissue.

CONCLUSION

Taken together, eugenol could protect broilers against ST infection via maintaining intestinal flora, tight junctions involved in mucosal barrier function, then accordingly limiting the excessive inflammation, finally contributed to improving relative weight gains and survival rates of broilers.

Transcriptional Regulation during Aberrant Activation of NF-κB Signalling in Cancer

The NF-κB signalling pathway is a major signalling cascade involved in the regulation of inflammation and innate immunity. It is also increasingly recognised as a crucial player in many steps of cancer initiation and progression. The five members of the NF-κB family of transcription factors are activated through two major signalling pathways, the canonical and non-canonical pathways. The canonical NF-κB pathway is prevalently activated in various human malignancies as well as inflammation-related disease conditions. Meanwhile, the significance of non-canonical NF-κB pathway in disease pathogenesis is also increasingly recognized in recent studies. In this review, we discuss the double-edged role of the NF-κB pathway in inflammation and cancer, which depends on the severity and extent of the inflammatory response. We also discuss the intrinsic factors, including selected driver mutations, and extrinsic factors, such as tumour microenvironment and epigenetic modifiers, driving aberrant activation of NF-κB in multiple cancer types. We further provide insights into the importance of the interaction of NF-κB pathway components with various macromolecules to its role in transcriptional regulation in cancer. Finally, we provide a perspective on the potential role of aberrant NF-κB activation in altering the chromatin landscape to support oncogenic development.

An Expanded Interplay Network between NF-κB p65 (RelA) and E2F1 Transcription Factors: Roles in Physiology and Pathology

Transcription Factors (TFs) are the main regulators of gene expression, controlling among others cell homeostasis, identity, and fate. TFs may either act synergistically or antagonistically on nearby regulatory elements and their interplay may activate or repress gene expression. The family of NF-κB TFs is among the most important TFs in the regulation of inflammation, immunity, and stress-like responses, while they also control cell growth and survival, and are involved in inflammatory diseases and cancer. The family of E2F TFs are major regulators of cell cycle progression in most cell types. Several studies have suggested the interplay between these two TFs in the regulation of numerous genes controlling several biological processes. In the present study, we compared the genomic binding landscape of NF-κB RelA/p65 subunit and E2F1 TFs, based on high throughput ChIP-seq and RNA-seq data in different cell types. We confirmed that RelA/p65 has a binding profile with a high preference for distal enhancers bearing active chromatin marks which is distinct to that of E2F1, which mostly generates promoter-specific binding. Moreover, the RelA/p65 subunit and E2F1 cistromes have limited overlap and tend to bind chromatin that is in an active state even prior to immunogenic stimulation. Finally, we found that a fraction of the E2F1 cistrome is recruited by NF-κΒ near pro-inflammatory genes following LPS stimulation in immune cell types.

Circular RNAs Involved in the Regulation of the Age-Related Pathways

Circular RNAs (circRNAs) are a class of covalently circular noncoding RNAs that have been extensively studied in recent years. Aging is a process related to functional decline that is regulated by signal transduction. An increasing number of studies suggest that circRNAs can regulate aging and multiple age-related diseases through their involvement in age-related signaling pathways. CircRNAs perform several biological functions, such as acting as miRNA sponges, directly interacting with proteins, and regulating transcription and translation to proteins or peptides. Herein, we summarize research progress on the biological functions of circRNAs in seven main age-related signaling pathways, namely, the insulin-insulin-like, PI3K-AKT, mTOR, AMPK, FOXO, p53, and NF-κB signaling pathways. In these pathways, circRNAs mainly function as miRNA sponges. In this review, we suggest that circRNAs are widely involved in the regulation of the main age-related pathways and are potential biomarkers for aging and age-related diseases.

Rutin Suppresses DMBA Carcinogenesis in the Breast Through Modulating IL-6/NF-κB, SRC1/HSP90 and ER-α

Rutin dietary supplements may offer pharmacological benefits as anticancer and antiinflammatory properties. This study aimed to investigate the inhibitory and protective effect of rutin on signaling pathways of mammary gland carcinogenesis expermintally induced in female rats by 7,12-di-methyl benz (a) anthracene (DMBA). Results showed that rutin administration ameliorated DMBA toxicity and carcinogic effect on kidney and liver revealed by a significant decrease of urea and creatinine levels, and the activity of the liver enzymes alanine aminotransferase (ALT) and alkaline phosphatase (ALP). The antioxidant state indicated by the total antioxidant capacity (TAC) was significantly increased accompanied by a reduction in the inflammatory markers of interleukin-1β (IL-1B), interleukin-6 (IL-6), and tumor necrosis factor (TNF-α) with induction of apoptosis indicated by a significant increase in caspase-3 level. Rutin significantly reduced the levels of the tumor markers carcinoma antigen 15-3 (CA 15-3) and proto-oncogene tyrosine-protein kinase Src1 (Src1). along with downregulation of nuclear factor-kB (NF-κB), heat shock protein 90 (HSP 90), and inducible nitric oxide synthase (iNOS) gene expression. The present study demonstrated the beneficial anticancer activity of rutin as a protective and therapeutic agent. Rutin induces its antitumor activity through elevation of the antioxidant state, inhibition of inflammatory cytokines, downregulation of oncogenes expression, and stimulation of apoptosis.

NF-κB: A Druggable Target in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is an aggressive hematological malignancy that relies on highly heterogeneous cytogenetic alterations. Although in the last few years new agents have been developed for AML treatment, the overall survival prospects for AML patients are still gloomy and new therapeutic options are still urgently needed. Constitutive NF-κB activation has been reported in around 40% of AML patients, where it sustains AML cell survival and chemoresistance. Given the central role of NF-κB in AML, targeting the NF-κB pathway represents an attractive strategy to treat AML. This review focuses on current knowledge of NF-κB's roles in AML pathogenesis and summarizes the main therapeutic approaches used to treat NF-κB-driven AML.

Salmonella enterica serovar Typhi influences inflammation and autophagy in macrophages

Salmonella enterica serovar Typhi (S. Typhi) is a human enteropathogen that can survive in macrophages and cause systemic infection. Autophagy and inflammation are two important immune responses of macrophages that contribute to the elimination of pathogens. However, Salmonella has derived many strategies to evade inflammation and autophagy. This study investigated inflammation-related NF-κB signaling pathways and autophagy in S. Typhi-infected macrophages. RNA-seq and quantitative real-time PCR indicated that mRNA levels of NF-κB signaling pathway and autophagy-related genes were dynamically influenced in S. Typhi-infected macrophages. Western blots revealed that S. Typhi activated the NF-κB signaling pathway and induced the expression of inhibitor protein IκBζ. In addition, S. Typhi enhanced autophagy during early stages of infection and may inhibit autophagy during late stages of infection. Thus, we propose that S. Typhi can influence the NF-κB signaling pathway and autophagy in macrophages.

Bone marrow granulocytes downregulate IL-1β and TNF production and the microbicidal activity of inflammatory macrophages

Macrophages play critical roles in inflammation and defense against pathogens, as well as in the return to tissue homeostasis. Macrophage subpopulations displaying antagonistic phenotypes are generally classified as proinflammatory M1, implicated in antipathogen and antitumoral activities, or as anti-inflammatory M2, associated with tissue repair. Granulocytic and monocytic myeloid-derived suppressor cells recruited from the bone marrow to tissues and phagocytosis of apoptotic neutrophils can attenuate macrophage microbicidal activity. Here, we showed that bone marrow neutrophils, but not thioglycollate-recruited neutrophils, directly suppress the responses of macrophages that were previously committed to an inflammatory phenotype. Cocultures of inflammatory macrophages with bone marrow CD11b+Ly6Ghi granulocytes led to reduced release of IL-1β, TNF-α, and IL-6 by macrophages after lipopolysaccharide stimulation. The suppressive activity was unrelated to granulocyte apoptosis or to secreted factors and required cell-to-cell contact. The suppressive effect was paralleled by reduction in the nuclear levels of the NF-κB p65 subunit, but not of the p50 subunit. Furthermore, bone marrow granulocytes decreased the phagocytic activity of macrophages and their capacity to kill intracellular Escherichia coli. Taken together, these results show that bone marrow granulocytes can function as suppressors of the proinflammatory activity and microbial-killing responses of macrophages.

NF-κB: A Double-Edged Sword Controlling Inflammation

Inflammation, when properly mounted and precisely calibrated, is a beneficial process that enables the rapid removal of invading pathogens and/or cellular corpses and promotes tissue repair/regeneration to restore homeostasis after injury. Being a paradigm of a rapid response transcription factor, the nuclear factor-kappa B (NF-κB) transcription factor family plays a central role in amplifying inflammation by inducing the expression of inflammatory cytokines and chemokines. Additionally, NF-κB also induces the expression of pro-survival and -proliferative genes responsible for promoting tissue repair and regeneration. Paradoxically, recent studies have suggested that the NF-κB pathway can also exert inhibitory effects on pro-inflammatory cytokine production to temper inflammation. Here, we review our current understanding about the pro- and anti-inflammatory roles of NF-κB and discuss the implication of its dichotomous inflammation-modulating activity in the context of inflammasome activation and tumorigenesis.

Green tea peptides ameliorate diabetic nephropathy by inhibiting the TGF-β/Smad signaling pathway in mice

Diabetic nephropathy (DN) is the most important cause of middle and late-stage chronic kidney disease. Green tea polypeptides are extracted from tea pomace, and exhibit various pharmacological effects. In this study, we analyzed the reno-protective effects of green tea peptides in diabetic db/db mice, and explored the underlying mechanisms. Peptide treatment for 5 weeks significantly reduced the blood glucose levels and other indices of diabetes, and alleviated renal injury measured in terms of blood creatinine, urea nitrogen and urinary albumin/urinary creatinine levels. Mechanistically, the green tea peptides downregulated p-Smad2/3, α-SMA, ZO-1 and vimentin proteins in the kidney tissues, and elevated Smad7. Thus, green tea peptides inhibited the deposition of ECM proteins by suppressing excessive activation of the TGF-β/Smad signaling pathway and reducing fibronectin levels. On the other hand, tea peptides ameliorated renal injury by inhibiting the production of inflammatory factors (iNOS and TNF-α) by suppressing the NF-κB signaling pathway. In addition, we confirmed the inhibitory effect of green tea peptides on the TGF-β/Smad signaling pathway in TGF-β1-stimulated HK-2 cells. Therefore, tea peptides can be considered as an effective candidate for alleviating DN.

Macrophage membrane-functionalized nanofibrous mats and their immunomodulatory effects on macrophage polarization

Immunomodulation is an important phenomenon in the normal mammalian host response toward an injury, and plays a critical role in tissue regeneration and regenerative medicine. Different phenotypes of macrophages show an array of activation states compassing pro-inflammatory to pro-alleviating cells, which are the critical players to modulate immune response and tissue regeneration. In this study, macrophage membranes of different phenotypes (macrophages (M0), classically activated macrophages (M1) and alternatively activated macrophages (M2)) were coated onto poly-ε-caprolactone (PCL) nanofibers to acquire exterior surface proteins and similar functions of the natural membranes. In vitro results unveiled that these nanofibers, especially the M2-PCL nanofibers, can suppress the activities of inflammatory markers such as TNF-α and IL-1β, and stimulate anti-inflammatory markers such as Arg-1, IL-10 and TGF-β. In a C57BL/6 mouse model, the macrophage membrane-coated nanofibers, especially the M2-PCL nanofibers, displayed minimal cellular infiltration and low collagen deposition, increased anti-inflammatory CD206 and decreased inflammatory CD86 levels. The M2-PCL nanofibers most effectively neutralized inflammatory chemokines, regulated the expression of inflammation-associated genes as well as anti-inflammatory genes, and showed strong immunomodulatory effects than the PCL, M0-PCL and M1-PCL nanofibers. STATEMENT OF SIGNIFICANCE: Different types of macrophage membrane-functionalized PCL nanofibers were successfully prepared and well characterized. They inherited the surface proteins imitating the source macrophages, and played an important role in limiting cellular infiltration and collagen deposition. These different macrophages and their membrane-coated nanofibers (M0-PCL, M1-PCL and M2-PCL) behaved like their respective source cells. The M2 mimicking M2-PCL nanofibers effectively polarized macrophages to M2 phenotype and decreased the expression of inflammation-associated chemokines and promoted the anti-inflammation in vitro and in vivo, which is critical for tissue regeneration. The mice implanted with the bio-mimicking M2-PCL nanofibers effectively inhibited toll like receptors signaling induced NF-kB and IRF-5 and their target genes such as Edn-1, IL-6, iNOS, TNF-α, etc. compared to the PCL, and M0-PCL and M1-PCL macrophage membrane-coated nanofibers.

LncRNA Uc003xsl.1-Mediated Activation of the NFκB/IL8 Axis Promotes Progression of Triple-Negative Breast Cancer

Aberrant activation of NFκB orchestrates a critical role in tumor carcinogenesis; however, the regulatory mechanisms underlying this activation are not fully understood. Here we report that a novel long noncoding RNA (lncRNA) Uc003xsl.1 is highly expressed in triple-negative breast cancer (TNBC) and correlates with poor outcomes in patients with TNBC. Uc003xsl.1 directly bound nuclear transcriptional factor NFκB-repressing factor (NKRF), subsequently preventing NKRF from binding to a specific negative regulatory element in the promoter of the NFκB-responsive gene IL8 and abolishing the negative regulation of NKRF on NFκB-mediated transcription of IL8. Activation of the NFκB/IL8 axis promoted the progression of TNBC. Trop2-based antibody-drug conjugates have been applied in clinical trials in TNBC. In this study, a Trop2-targeting, redox-responsive nanoparticle was developed to systematically deliver Uc003xsl.1 siRNA to TNBC cells in vivo, which reduced Uc003xsl.1 expression and suppressed TNBC tumor growth and metastasis. Therefore, targeting Uc003xsl.1 to suppress the NFκB/IL8 axis represents a promising therapeutic strategy for TNBC treatment.

SIGNIFICANCE

These findings identify an epigenetic-driven NFκB/IL8 cascade initiated by a lncRNA, whose aberrant activation contributes to tumor metastasis and poor survival in patients with triple-negative breast cancer.

Molecular docking investigation of calotropone as a potential natural therapeutic agent against pancreatic cancer

A natural bioactive compound named calotropone has been reported as a drug candidate for several cancers, including pancreatic cancers. Herein, we used molecular docking approach to test the possible mechanisms of action of calotropone in inhibiting the growth of pancreatic cell cancer with gemcitabine as the positive control. By employing AutoDock Vina, we studied the molecular interaction between calotropone and pancreatic cancer-associated proteins, namely Glucosaminyl (N-Acetyl) Transferase 3, Glutamic-Oxaloacetic Transaminase 1, Tyrosine-protein kinase Met (c-Met), peroxisome proliferator-activated receptor γ, Budding Uninhibited by Benzimidazole 1, A Disintegrin and Metalloproteinase 10, Sex-determining region Y and Nuclear Factor kappa Beta (Nf-Kβ). Higher affinity energies of calotropone toward the aforementioned proteins (ranging from ‒7.3 to ‒9.3 kcal/mol) indicate that calotropone may work in the same manner as anticancer drug gemcitabine. Highest docking score was found at the interaction of calotropone and Nf-Kβ (‒9.3 kcal/mol).

Hemoglobin induces inflammation through NF-kB signaling pathway and causes cell oxidative damage in grass carp (Ctenopharyngodon idella)

Hemolytic disease in grass carp (C. idella) leads to hemolysis in vivo, releasing damage-related molecular patterns (DAMPs) hemoglobin (Hb; which is rapidly oxidized to Hb-Fe³⁺ and Hb-Fe⁴⁺) and generating a high level of reactive oxygen species (ROS) that cause oxidative damage. However, the effect of cell-free Hb on tissue cells of grass carp has yet to be elucidated. In this study, western blotting (WB) and immunofluorescence analysis (IFA) results showed that PHZ-induced hemolysis caused Hb and iron accumulation, increased the production of ROS and resulted in apoptosis in head kidney and middle kidney of the grass carp. Quantitative real-time PCR (qRT-PCR), WB, and IFA revealed that PHZ-induced hemolysis significantly upregulated the expression of inflammation-related genes through activation of the NF-κB signaling pathway. To further explore the effect of Hb, three forms of Hb (Hb, MetHb, and FerrylHb) were prepared. The incubation with the different forms of Hb and heme markedly upregulated the expression of cytokine genes through NF-κB signaling pathway, which was further confirmed by a specific inhibitor (caffeic acid phenethyl ester, CAPE). Flow cytometry analysis data showed that the stimulation of different forms of Hb and heme increased the production of ROS, and resulted in apoptosis. In summary, our data suggest that the excess cell-free Hb released during hemolysis modulates the inflammatory response through activation of the NF-κB signaling pathway and causes cell oxidative damage and apoptosis.

Magnolol protects against acute gastrointestinal injury in sepsis by down-regulating regulated on activation, normal T-cell expressed and secreted

BACKGROUND

Sepsis is a major medical challenge. Magnolol is an active constituent of Houpu that improves tissue function and exerts strong anti-endotoxin and anti-inflammatory effects, but the mechanism by which it reduces intestinal inflammation in sepsis is yet unclear.

AIM

To assess the protective effect of magnolol on intestinal mucosal epithelial cells in sepsis and elucidate the underlying mechanisms.

METHODS

Enzyme-linked immunosorbent assay was used to measure tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and regulated on activation, normal T-cell expressed and secreted (RANTES) levels in serum and ileal tissue in animal studies. The histopathological changes of the ileal mucosa in different groups were observed under a microscope. Cell Counting Kit-8 and cell permeability assays were used to determine the concentration of drug-containing serum that did not affect the activity of Caco2 cells but inhibited lipopolysaccharide (LPS)-induced decrease in permeability. Immunofluorescence and Western blot assays were used to detect the levels of RANTES, inhibitor of nuclear factor kappa-B kinase β (IKKβ), phosphorylated IKKβ (p-IKKβ), inhibitor of nuclear factor kappa-B kinase α (IκBα), p65, and p-p65 proteins in different groups in vitro.

RESULTS

In rats treated with LPS by intravenous tail injection in the presence or absence of magnolol, magnolol inhibited the expression of proinflammatory cytokines, IL-1β, IL-6, and TNF-α in a dose-dependent manner. In addition, magnolol suppressed the production of RANTES in LPS-stimulated sepsis rats. Moreover, in vitro studies suggested that magnolol inhibited the increase of p65 nucleation, thereby markedly downregulating the production of the phosphorylated form of IKKβ in LPS-treated Caco2 cells. Specifically, magnolol inhibited the translocation of the transcription factor nuclear factor-kappa B (NF-κB) from the cytosol into the nucleus and down-regulated the expression level of the chemokine RANTES in LPS-stimulated Caco2 cells.

CONCLUSION

Magnolol down-regulates RANTES levels by inhibiting the LPS/NF-κB signaling pathways, thereby suppressing IL-1β, IL-6, and TNF-α expression to alleviate the mucosal barrier dysfunction in sepsis.

A tale of two proteins: PACT and PKR and their roles in inflammation

Inflammation is a pathological hallmark associated with bacterial and viral infections, autoimmune diseases, genetic disorders, obesity and diabetes, as well as environmental stresses including physical and chemical trauma. Among numerous proteins regulating proinflammatory signaling, very few such as Protein kinase R (PKR), have been shown to play an all-pervading role in inflammation induced by varied stimuli. PKR was initially characterized as an interferon-inducible gene activated by viral double-stranded RNA with a role in protein translation inhibition. However, it has become increasingly clear that PKR is involved in multiple pathways that promote inflammation in response to stress activation, both dependent on and independent of its cellular protein activator of PKR (PACT). In this review, we discuss the signaling pathways that contribute to the initiation of inflammation, including Toll-like receptor, interferon, and RIG-I-like receptor signaling, as well as inflammasome activation. We go on to discuss the specific roles that PKR and PACT play in such proinflammatory signaling, as well as in metabolic syndrome- and environmental stress-induced inflammation.

The Health Hazards of Volcanoes: First Evidence of Neuroinflammation in the Hippocampus of Mice Exposed to Active Volcanic Surroundings

Neuroinflammation is a process related to the onset of neurodegenerative diseases; one of the hallmarks of this process is microglial reactivation and the secretion by these cells of proinflammatory cytokines such as TNFα. Numerous studies report the relationship between neuroinflammatory processes and exposure to anthropogenic air pollutants, but few refer to natural pollutants. Volcanoes are highly inhabited natural sources of environmental pollution that induce changes in the nervous system, such as reactive astrogliosis or the blood-brain barrier breakdown in exposed individuals; however, no neuroinflammatory event has been yet defined. To this purpose, we studied resting microglia, reactive microglia, and TNFα production in the brains of mice chronically exposed to an active volcanic environment on the island of São Miguel (Azores, Portugal). For the first time, we demonstrate a proliferation of microglial cells and an increase in reactive microglia, as well an increase in TNFα secretion, in the central nervous system of individuals exposed to volcanogenic pollutants.

Reactive Oxygen Species in Acute Lymphoblastic Leukaemia: Reducing Radicals to Refine Responses

Acute lymphoblastic leukaemia (ALL) is the most common cancer diagnosed in children and adolescents. Approximately 70% of patients survive >5-years following diagnosis, however, for those that fail upfront therapies, survival is poor. Reactive oxygen species (ROS) are elevated in a range of cancers and are emerging as significant contributors to the leukaemogenesis of ALL. ROS modulate the function of signalling proteins through oxidation of cysteine residues, as well as promote genomic instability by damaging DNA, to promote chemotherapy resistance. Current therapeutic approaches exploit the pro-oxidant intracellular environment of malignant B and T lymphoblasts to cause irreversible DNA damage and cell death, however these strategies impact normal haematopoiesis and lead to long lasting side-effects. Therapies suppressing ROS production, especially those targeting ROS producing enzymes such as the NADPH oxidases (NOXs), are emerging alternatives to treat cancers and may be exploited to improve the ALL treatment. Here, we discuss the roles that ROS play in normal haematopoiesis and in ALL. We explore the molecular mechanisms underpinning overproduction of ROS in ALL, and their roles in disease progression and drug resistance. Finally, we examine strategies to target ROS production, with a specific focus on the NOX enzymes, to improve the treatment of ALL.

A novel role of snail in regulating tuberin/AMPK pathways to promote renal fibrosis in the new mouse model of type II diabetes

Epithelial-mesenchymal transition (EMT) plays an important role in tissue fibrosis following chronic exposure to hyperglycemia. This study investigates the role of chronic diabetes in regulating tuberin/snail/AMPK to enhance EMT and increase renal fibrosis. A new mouse model of db/db/TSC2 ^+/- was generated by backcrossing db/db mice and TSC2 ^+/- mice. Wild type (WT), db/db, TSC2 ^+/- and dbdb/TSC2 ^+/- mice were sacrificed at ages 6 and 8 months old. Tuberin protein level was significantly decreased in kidneys from diabetic compared to WT mice at both ages. In addition, tuberin and E-cadherin protein levels were significantly decreased in dbdb/TSC2 ^+/- compared to TSC2 ^+/- and db/db mice. In contrast, p-PS6K, NFkB, snail, vimentin, fibronectin, and α-SMA protein levels were significantly increased in dbdb/TSC2 ^+/- compared to db/db and TSC2 ^+/- mice at ages 6 and 8 months. Both downregulation of AMPK by DN-AMPK and downregulation of tuberin by siRNA resulted in increased NFkB, snail, and fibronectin protein expression and decreased E-cadherin protein expression in mouse primary renal proximal tubular cells. Interestingly, downregulation of snail by siRNA increased tuberin expression via feedback through activation of AMPK and reversed the expression of epithelial proteins such as E-cadherin as well as mesenchymal proteins such as fibronectin, NF-KB, vimentin, and α-SMA in mouse primary renal proximal tubular cells isolated from kidneys of four mice genotypes. The data show that chronic diabetes significantly decreases tuberin expression and that provides strong evidence that tuberin is a major key protein involved in regulating EMT. These data also demonstrated a novel role for snail in regulating of AMPK/tuberin to enhance EMT and renal cell fibrosis in diabetes.

Suramin attenuates intervertebral disc degeneration by inhibiting NF-κB signalling pathway

Aims

Interleukin (IL)-1β is one of the major pathogenic regulators during the pathological development of intervertebral disc degeneration (IDD). However, effective treatment options for IDD are limited. Suramin is used to treat African sleeping sickness. This study aimed to investigate the pharmacological effects of suramin on mitigating IDD and to characterize the underlying mechanism.

Methods

Porcine nucleus pulposus (NP) cells were treated with vehicle, 10 ng/ml IL-1β, 10 μM suramin, or 10 μM suramin plus IL-1β. The expression levels of catabolic and anabolic proteins, proinflammatory cytokines, mitogen-activated protein kinase (MAPK), and nuclear factor (NF)-κB-related signalling molecules were assessed by Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), and immunofluorescence analysis. Flow cytometry was applied to detect apoptotic cells. The ex vivo effects of suramin were examined using IDD organ culture and differentiation was analyzed by Safranin O-Fast green and Alcian blue staining.

Results

Suramin inhibited IL-1β-induced apoptosis, downregulated matrix metalloproteinase (MMP)-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, and ADAMTS-5, and upregulated collagen 2A (Col2a1) and aggrecan in IL-1β-treated NP cells. IL-1β-induced inflammation, assessed by IL-1β, IL-8, and tumour necrosis factor α (TNF-α) upregulation, was alleviated by suramin treatment. Suramin suppressed IL-1β-mediated proteoglycan depletion and the induction of MMP-3, ADAMTS-4, and pro-inflammatory gene expression in ex vivo experiments.

Conclusion

Suramin administration represents a novel and effectively therapeutic approach, which could potentially alleviate IDD by reducing extracellular matrix (ECM) deposition and inhibiting apoptosis and inflammatory responses in the NP cells.

Cite this article: Bone Joint Res 2021;10(8):498–513.

Emodin resists to Cyprinid herpesvirus 3 replication via the pathways of Nrf2/Keap1-ARE and NF-κB in the ornamental koi carp (Cyprinus carpio haematopterus)

Cyprinid herpesvirus 3 (CyHV-3) causes high mortality in carp. Emodin has been shown of the effects of antioxidant, anti-inflammatory and antiviral. In present study, we investigated the preventive effects and mechanism of emodin on CyHV-3 infection. The ornamental koi carp (Cyprinus carpio haematopterus) were intraperitoneally injected with emodin (10 mg/kg, 20 mg/kg, or 40 mg/kg). 72 h later, an intraperitoneal injection of CyHV-3 was administered, and collected the samples one week later to detect the antioxidant parameters, antioxidant genes, inflammatory genes and to perform histopathology assays. The results showed that emodin significantly suppressed CyHV-3 replication (P < 0.05), improved the koi survival rate and slowed the damage caused by CyHV-3. Emodin treatment increased the antioxidant activity and decreased the lipid peroxidation level of the koi. Compared to the CyHV-3 group, emodin treatment resulted in the same antioxidant parameters after CyHV-3 infection. Emodin treatment activated the Nuclear factorery throid 2-related factor 2/Kelch-like ECH-associated protein 1-antioxidatant response element (Nrf2/Keap1-ARE) pathway and upregulated the expression of heme oxygenase 1 (HO-1), superoxide dismutase (SOD), and catalase (CAT) in the hepatopancreas after CyHV-3 infection. Emodin activated the nuclear factor kappa-B (NF-κB) pathway and decreased the expression of interleukin-6 (IL-6), interleukin-8 (IL-8), and tumour necrosis factor-α (TNF-α) in the koi induced by CyHV-3. In conclusion, emodin treatment can suppress CyHV-3 replication and reduce the mortality of koi caused by CyHV-3. Emodin improves antioxidant function, relieves oxidative stress and inflammation cytokines via Nrf2/Keap1-ARE and NF-κB pathways, and protects against the adverse effects induced by CyHV-3.

TNF stimulation primarily modulates transcriptional burst size of NF-κB-regulated genes

Cell-to-cell heterogeneity is a feature of the tumor necrosis factor (TNF)-stimulated inflammatory response mediated by the transcription factor NF-κB, motivating an exploration of the underlying sources of this noise. Here, we combined single-transcript measurements with computational models to study transcriptional noise at six NF-κB-regulated inflammatory genes. In the basal state, NF-κB-target genes displayed an inverse correlation between mean and noise characteristic of transcriptional bursting. By analyzing transcript distributions with a bursting model, we found that TNF primarily activated transcription by increasing burst size while maintaining burst frequency for gene promoters with relatively high basal histone 3 acetylation (AcH3) that marks open chromatin environments. For promoters with lower basal AcH3 or when AcH3 was decreased with a small molecule drug, the contribution of burst frequency to TNF activation increased. Finally, we used a mathematical model to show that TNF positive feedback amplified gene expression noise resulting from burst size-mediated transcription, leading to a subset of cells with high TNF protein expression. Our results reveal potential sources of noise underlying intercellular heterogeneity in the TNF-mediated inflammatory response.

Myocardin-Related Transcription Factor A Mediates LPS-Induced iNOS Transactivation

Macrophage-dependent inflammation plays a critical role in atherogenesis. Inducible nitric oxide synthase (iNOS) is one of key pro-inflammatory mediators produced in macrophages and its levels can be upregulated by lipopolysaccharide (LPS). The epigenetic mechanism whereby LPS induces iNOS transcription is incompletely understood. We show here myocardin-related transcription factor A (MRTF-A) potentiated iNOS promoter activity in macrophages. There was a decrease in LPS-induced iNOS expression in several cell models due to the lack of MRTF-A. LPS treatment promoted nuclear accumulation of MRTF-A and its interaction with NF-κB/p65 on the iNOS promoter. The absence of MRTF-A prevented the accumulation of active histone marks on the iNOS promoter in response to LPS treatment. Mechanistically, MRTF-A recruited ASH2, a key component of the mammalian histone H3K4 methyltransferase complex, to the iNOS promoter. Silencing of ASH2 attenuated iNOS expression following LPS treatment. Together, our data highlight a role for MRTF-A-dependent recruitment of H3K4 methyltransferase in iNOS induction and as such provide a novel target in the intervention of atherosclerosis.

Transcription factor NF-κB unravels nucleosomes

NF-κB is a transcription factor responsible for activating hundreds of genes in mammalian organisms. To accomplish its function, NF-κB must interact with DNA occupied by nucleosomes, but how this interaction occurs is unclear. Here we used Atomic Force Microscopy to characterize complexes of NF-κB with nucleosomes assembled on different DNA templates. The assembly of NF-κB-nucleosome complexes leads to a substantial decrease of DNA wrapping efficiency from 149 ± 2 bp (SEM) for the control nucleosome sample to 135 ± 3 bp for complexes of nucleosomes with NF-κB. Mapping of the nucleosomes did not reveal displacement of under-wrapped nucleosomes from their original position, suggesting that unravelling involves dissociation of one or both flanks of the nucleosomes. Binding of NF-κB to the core was identified by nucleosome core volume measurements. We discovered two binding modes of NF-κB associated with nucleosome unravelling - NF-κB bound to the nucleosome core and to the DNA flanks. From these findings we propose two models explaining the interaction of NF-κB with the nucleosome complex. The partial unravelling of nucleosomes by NF-κB makes the DNA segment at the edge of the nucleosome core accessible, facilitating the transcription process. We speculate that NF-κB can function as a pioneer factor, enhancing its ability to facilitate rapid transcriptional response to cell stress.

Cascades between miRNAs, lncRNAs and the NF-κB signaling pathway in gastric cancer (Review)

Gastric cancer is a common digestive tract malignancy that is mainly treated with surgery combined with perioperative adjuvant chemoradiotherapy and biological targeted therapy. However, the diagnosis rate of early gastric cancer is low and both postoperative recurrence and distant metastasis are thorny problems. Therefore, it is essential to study the pathogenesis of gastric cancer and search for more effective means of treatment. The nuclear factor-κB (NF-κB) signaling pathway has an important role in the occurrence and development of gastric cancer and recent studies have revealed that microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are able to regulate this pathway through a variety of mechanisms. Understanding these interrelated molecular mechanisms is helpful in guiding improvements in gastric cancer treatment. In the present review, the functional associations between miRNAs, lncRNAs and the NF-κB signaling pathway in the occurrence, development and prognosis of gastric cancer were discussed. It was concluded that miRNAs and lncRNAs have complex relations with the NF-κB signaling pathway in gastric cancer. miRNAs/target genes/NF-κB/target proteins, signaling molecules/NF-κB/miRNAs/target genes, lncRNAs/miRNAs/NF-κB/genes or mRNAs, lncRNAs/target genes/NF-Κb/target proteins, and lncRNAs/NF-κB/target proteins cascades are all important factors in the occurrence and development of gastric cancer.

Regulation of Transcription Factor NF-κB in Its Natural Habitat: The Nucleus

Activation of the transcription factor NF-κB elicits an individually tailored transcriptional response in order to meet the particular requirements of specific cell types, tissues, or organs. Control of the induction kinetics, amplitude, and termination of gene expression involves multiple layers of NF-κB regulation in the nucleus. Here we discuss some recent advances in our understanding of the mutual relations between NF-κB and chromatin regulators also in the context of different levels of genome organization. Changes in the 3D folding of the genome, as they occur during senescence or in cancer cells, can causally contribute to sustained increases in NF-κB activity. We also highlight the participation of NF-κB in the formation of hierarchically organized super enhancers, which enable the coordinated expression of co-regulated sets of NF-κB target genes. The identification of mechanisms allowing the specific regulation of NF-κB target gene clusters could potentially enable targeted therapeutic interventions, allowing selective interference with subsets of the NF-κB response without a complete inactivation of this key signaling system.

Dietary polyphenols suppress chronic inflammation by modulation of multiple inflammation-associated cell signaling pathways

The high failure rate of the reductionist approach to discover effective and safe drugs to treat chronic inflammatory diseases has led scientists to seek alternative ways. Recently, targeting cell signaling pathways has been utilized as an innovative approach to discover drug leads from natural products. Cell signaling mechanisms have been identified playing key role in diverse diseases by inducing proliferation, cell survival and apoptosis. Phytochemicals are known to be able to modulate the cellular and molecular networks which are associated to chronic diseases including cancer-associated inflammation. In this review, the roles of dietary polyphenols (apigenin, kaempferol, quercetin, curcumin, genistein, isoliquiritigenin, resveratrol and gallic acid) in modulating multiple inflammation-associated cell signaling networks are deliberated. Scientific databases on suppressive effects of the polyphenols on chronic inflammation via modulation of the pathways especially in the recent five years are gathered and critically analyzed. The polyphenols are able to modulate several inflammation-associated cell signaling pathways, namely nuclear factor-kappa β, mitogen activated protein kinases, Wnt/β-catenin and phosphatidylinositol 3-kinase and protein kinase B via selective actions on various components of the networks. The suppressive effects of the polyphenols on the multiple cell signaling pathways reveal their potential use in prevention and treatment of chronic inflammatory disorders. Understanding the mechanistic effects involved in modulation of the signaling pathways by the polyphenols is necessary for lead identification and development of future functional foods for prevention and treatment of chronic inflammatory diseases.

The Biological Significance of Targeting Acetylation-Mediated Gene Regulation for Designing New Mechanistic Tools and Potential Therapeutics

The molecular interplay between nucleosomal packaging and the chromatin landscape regulates the transcriptional programming and biological outcomes of downstream genes. An array of epigenetic modifications plays a pivotal role in shaping the chromatin architecture, which controls DNA access to the transcriptional machinery. Acetylation of the amino acid lysine is a widespread epigenetic modification that serves as a marker for gene activation, which intertwines the maintenance of cellular homeostasis and the regulation of signaling during stress. The biochemical horizon of acetylation ranges from orchestrating the stability and cellular localization of proteins that engage in the cell cycle to DNA repair and metabolism. Furthermore, lysine acetyltransferases (KATs) modulate the functions of transcription factors that govern cellular response to microbial infections, genotoxic stress, and inflammation. Due to their central role in many biological processes, mutations in KATs cause developmental and intellectual challenges and metabolic disorders. Despite the availability of tools for detecting acetylation, the mechanistic knowledge of acetylation-mediated cellular processes remains limited. This review aims to integrate molecular and structural bases of KAT functions, which would help design highly selective tools for understanding the biology of KATs toward developing new disease treatments.

Interactions between Salmonella and host macrophages - Dissecting NF-κB signaling pathway responses

Salmonella not only invades host cells, but also replicates intracellularly to cause a range of diseases, including gastroenteritis and systemic infections such as typhoid fever. The body's first line of defense against pathogens is the innate immune response system that can protect against Salmonella invasion and replication. Nuclear factor κB (NF-κB) is an important transcriptional regulator that plays an important role in host inflammatory responses to pathogens. Both the canonical and non-canonical NF-κB signaling pathways are activated by Salmonella in many different ways through its virulence factors, leading to the release of inflammatory factors and the activation of inflammatory responses in mammalian hosts. Equally, Salmonella, as an enteropathogen, has accordingly evolved strategies to disturb NF-κB activation, such as secreting some effector proteins by type III secretion systems as well as inducing host cells to express NF-κB pathway inhibitors, allowing it to colonize and persistently infect the hosts. This review focuses on how Salmonella activates NF-κB signaling pathway and the strategies used by Salmonella to interfere with the NF-κB pathway activation.

Perspectives on the Clinical Development of NRF2-Targeting Drugs

The transcription factor NRF2 (nuclear factor erythroid 2-related factor 2) triggers homeostatic responses against a plethora of environmental or endogenous deviations in redox metabolism, inflammation, proteostasis, etc. Therefore, pharmacological activation of NRF2 is a promising therapeutic strategy for several chronic diseases that are underlined by low-grade oxidative inflammation and dysregulation of redox metabolism, such as neurodegenerative, cardiovascular, and metabolic diseases. While NRF2 activation is useful in inhibiting carcinogenesis, its inhibition is needed in constituted tumors where NRF2 provides a survival advantage in the challenging tumor niche. This review describes the electrophilic and non-electrophilic NRF2 activators with clinical projection in various chronic diseases. We also analyze the status of NRF2 inhibitors, which are for the moment in a proof-of-concept stage. Advanced in silico screening and medicinal chemistry are expected to provide new or repurposing small molecules with increased potential for fostering the development of targeted NRF2 modulators. The nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2) is rapidly degraded by proteasomes under a basal condition in a Keap1-dependent manner. ROS oxidatively modifies Keap1 to release NRF2 and allow its nuclear translocation. Here it binds to the antioxidant response element to regulate gene transcription. An alternative mechanism controlling NRF2 stability is glycogen synthase kinase 3 (GSK-3)-induced phosphorylation. Indicated in blue are NRF2-activating and NRF2-inhibiting drugs.

IL-10 and class 1 histone deacetylases act synergistically and independently on the secretion of proinflammatory mediators in alveolar macrophages

Introduction

Anti-inflammatory cytokine IL-10 suppresses pro-inflammatory IL-12b expression after Lipopolysaccharide (LPS) stimulation in colonic macrophages, as part of the innate immunity Toll-Like Receptor (TLR)-NF-κB activation system. This homeostatic mechanism limits excess inflammation in the intestinal mucosa, as it constantly interacts with the gut flora. This effect is reversed with Histone Deacetylase 3 (HDAC3), a class I HDAC, siRNA, suggesting it is mediated through HDAC3. Given alveolar macrophages’ prominent role in Acute Lung Injury (ALI), we aim to determine whether a similar regulatory mechanism exists in the typically sterile pulmonary microenvironment.

Methods

Levels of mRNA and protein for IL-10, and IL-12b were determined by qPCR and ELISA/Western Blot respectively in naïve and LPS-stimulated alveolar macrophages. Expression of the NF-κB intermediaries was also similarly assessed. Experiments were repeated with AS101 (an IL-10 protein synthesis inhibitor), MS-275 (a selective class 1 HDAC inhibitor), or both.

Results

LPS stimulation upregulated all proinflammatory mediators assayed in this study. In the presence of LPS, inhibition of IL-10 and/or class 1 HDACs resulted in both synergistic and independent effects on these signaling molecules. Quantitative reverse-transcriptase PCR on key components of the TLR4 signaling cascade demonstrated significant diversity in IL-10 and related gene expression in the presence of LPS. Inhibition of IL-10 secretion and/or class 1 HDACs in the presence of LPS independently affected the transcription of MyD88, IRAK1, Rela and the NF-κB p50 subunit. Interestingly, by quantitative ELISA inhibition of IL-10 secretion and/or class 1 HDACs in the presence of LPS independently affected the secretion of not only IL-10, IL-12b, and TNFα, but also proinflammatory mediators CXCL2, IL-6, and MIF. These results suggest that IL-10 and class 1 HDAC activity regulate both independent and synergistic mechanisms of proinflammatory cytokine/chemokine signaling.

Conclusions

Alveolar macrophages after inflammatory stimulation upregulate both IL-10 and IL-12b production, in a highly class 1 HDAC-dependent manner. Class 1 HDACs appear to help maintain the balance between the pro- and anti-inflammatory IL-12b and IL-10 respectively. Class 1 HDACs may be considered as targets for the macrophage-initiated pulmonary inflammation in ALI in a preclinical setting.

The ARF tumor suppressor targets PPM1G/PP2Cγ to counteract NF-κB transcription tuning cell survival and the inflammatory response

Inducible transcriptional programs mediate the regulation of key biological processes and organismal functions. Despite their complexity, cells have evolved mechanisms to precisely control gene programs in response to environmental cues to regulate cell fate and maintain normal homeostasis. Upon stimulation with proinflammatory cytokines such as tumor necrosis factor-α (TNF), the master transcriptional regulator nuclear factor (NF)-κB utilizes the PPM1G/PP2Cγ phosphatase as a coactivator to normally induce inflammatory and cell survival programs. However, how PPM1G activity is precisely regulated to control NF-κB transcription magnitude and kinetics remains unknown. Here, we describe a mechanism by which the ARF tumor suppressor binds PPM1G to negatively regulate its coactivator function in the NF-κB circuit thereby promoting insult resolution. ARF becomes stabilized upon binding to PPM1G and forms a ternary protein complex with PPM1G and NF-κB at target gene promoters in a stimuli-dependent manner to provide tunable control of the NF-κB transcriptional program. Consistently, loss of ARF in colon epithelial cells leads to up-regulation of NF-κB antiapoptotic genes upon TNF stimulation and renders cells partially resistant to TNF-induced apoptosis in the presence of agents blocking the antiapoptotic program. Notably, patient tumor data analysis validates these findings by revealing that loss of ARF strongly correlates with sustained expression of inflammatory and cell survival programs. Collectively, we propose that PPM1G emerges as a therapeutic target in a variety of cancers arising from ARF epigenetic silencing, to loss of ARF function, as well as tumors bearing oncogenic NF-κB activation.

An antioxidative galactomannan extracted from Chinese Sesbania cannabina enhances immune activation of macrophage cells

In the present study, the antioxidant activities and immunostimulatory ability of a polysaccharide extracted from Chinese Sesbania cannabina, which was identified to be a galactomannan in our previous study, were investigated. The extracted polysaccharide exhibited strong DPPH, ABTS and hydroxyl radical scavenging activities and ferrous ion chelating activity in a concentration-dependent manner. The immune-enhancing effect of our polysaccharide on RAW 264.7 macrophage cells was investigated by determining the cell viability, phagocytic activity, NO and intracellular ROS production and mRNA expression of cytokines. The results indicated that the polysaccharide could increase the production of NO and intracellular ROS, as well as effectively trigger transcriptional activation of TLR-2/4, NF-κB, IL-10/1β/6, IFN-γ, Ik-Bα, iNOS, COX-2 and TNF-α. These findings provide useful information for potential application of the polysaccharide extracted from Chinese Sesbania cannabina in the food industry.

Combinatorial dynamics of protein synthesis time delay and negative feedback loop in NF-κB signalling pathway

The transcription factor NF-κB links immune response and inflammatory reaction and its different oscillation patterns determine different cell fates. In this study, a mathematical model with IκBα protein synthesis time delay is developed based on the experimental evidences. The results show that time delay has the ability to drive oscillation of NF-κB via Hopf bifurcation. Meanwhile, the amplitude and period are sensitive to the time delay. Moreover, the time delay threshold is a function of four parameters characterising the negative feedback loop. Likewise, the parameters also have effects on the amplitude and period of NF-κB oscillation induced by time delay. Therefore, the oscillation patterns of NF-κB are collaborative results of time delay coupled with the negative feedback loop. These results not only enhance the understanding of NF-κB biological oscillation but also provide clues for the development of anti-inflammatory or anti-cancer drugs.

Cell-Penetrable Peptide-Conjugated FADD Induces Apoptosis and Regulates Inflammatory Signaling in Cancer Cells

Dysregulated expression of Fas-associated death domain (FADD) is associated with the impediment of various cellular pathways, including apoptosis and inflammation. The adequate cytosolic expression of FADD is critical to the regulation of cancer cell proliferation. Importantly, cancer cells devise mechanisms to suppress FADD expression and, in turn, escape from apoptosis signaling. Formulating strategies, for direct delivery of FADD proteins into cancer cells in a controlled manner, may represent a promising therapeutic approach in cancer therapy. We chemically conjugated purified FADD protein with cell permeable TAT (transactivator of transcription) peptide, to deliver in cancer cells. TAT-conjugated FADD protein internalized through the caveolar pathway of endocytosis and retained in the cytosol to augment cell death. Inside cancer cells, TAT-FADD rapidly constituted DISC (death inducing signaling complex) assembly, which in turn, instigate apoptosis signaling. The apoptotic competency of TAT-FADD showed comparable outcomes with the conventional apoptosis inducers. Notably, TAT-FADD mitigates constitutive NF-κB activation and associated downstream anti-apoptotic genes Bcl2, cFLIP_L, RIP1, and cIAP2, independent of pro-cancerous TNF-α priming. In cancer cells, TAT-FADD suppresses the canonical NLRP3 inflammasome priming and restricts the processing and secretion of proinflammatory IL-1β. Our results demonstrate that TAT-mediated intracellular delivery of FADD protein can potentially recite apoptosis signaling with simultaneous regulation of anti-apoptotic and proinflammatory NF-κB signaling activation in cancer cells.

Sphingosine Kinases are Involved in Macrophage NLRP3 Inflammasome Transcriptional Induction

Recent studies suggested an important contribution of sphingosine-1-phospate (S1P) signaling via its specific receptors (S1PRs) in the production of pro-inflammatory mediators such as Interleukin (IL)-1β in cancer and inflammation. In an inflammation-driven cancer setting, we previously reported that myeloid S1PR1 signaling induces IL-1β production by enhancing NLRP3 (NOD-, LRR- and Pyrin Domain-Containing Protein 3) inflammasome activity. However, the autocrine role of S1P and enzymes acting on the S1P rheostat in myeloid cells are unknown. Using human and mouse macrophages with pharmacological or genetic intervention we explored the relative contribution of sphingosine kinases (SPHKs) in NLRP3 inflammasome activity regulation. We noticed redundancy in SPHK1 and SPHK2 activities towards macrophage NLRP3 inflammasome transcriptional induction and IL-1β secretion. However, pharmacological blockade of both kinases in unison completely abrogated NLRP3 inflammasome induction and IL-1β secretion. Interestingly, human and mouse macrophages demonstrate varied responses towards SPHKs inhibition and IL-1β secretion. Clinical datasets of renal cell carcinoma and psoriasis patients showed a positive correlation between enzymes affecting the S1P rheostat with NLRP3 inflammasome components expression, which corroborates our finding. Our data provide a better understanding on the role of SPHKs and de novo synthesized S1P in macrophage NLRP3 inflammasome activation.

Treatment of psoriasis with NFKBIZ siRNA using topical ionic liquid formulations

Systemic antibodies targeting tumor necrosis factor-α (TNF-α) and interleukin-17A (IL-17A) are effective in plaque psoriasis. Despite their popularity, safety concerns pose a challenge for systemic biologics. While anti-TNF-α and anti-IL-17A antibodies effectively inhibit respective proteins, we hypothesize that an approach based on local silencing of an upstream target such as NFKBIZ can be advantageous for treating psoriasis. However, effective delivery of small interfering RNA (siRNA) into the skin is a substantial hurdle due to skin's barrier function and poor stability of siRNA. Using ionic liquids as an enabling technology, we report on the effective delivery of NFKBIZ siRNA into the skin and its therapeutic efficacy in a psoriasis model. Treatment with IL-siRNA suppressed aberrant gene expression and resulted in down-regulation of psoriasis-related signals including TNF-α and IL-17A. These results provide a framework for a topical delivery platform for siRNA.

Pro-inflammatory immunological effects of adipose tissue and risk of food allergy in obesity: Focus on immunological mechanisms

Over the past three decades, the number of obese people has risen steadily. The chronic low-grade inflammatory state and the non-specific activation of the immune system have contributed greatly to the development of obesity-related immunology. Food allergy as a kind of inflammatory disease with abnormal immune response may be associated with obesity. This review begins with the pro-inflammatory immunological effects of adipose tissue in obesity, and explains the possible effects of obesity on food allergy. In short, obesity not only directly causes imbalance of allergic-related immune cells in adipose tissue, but also indirectly causes this consequence through affecting expression of adipocytokines and peroxisome proliferator-activated receptor gamma (PPARγ) in adipose tissue. As a result, circulating levels of pro-inflammatory factors which are partly derived from adipose tissue increase, which might cause intestinal barrier injury. Therefore, obesity may increase the risk of food allergy.

Small-Molecule Antagonist Targeting Exportin-1 via Rational Structure-Based Discovery

Exportin-1 (also named as CRM1) plays a prominent role in autoimmune disorders and has emerged as a potential therapeutic target for colitis. Here we report on the rational structure-based discovery of a small-molecule antagonist of exportin-1, LFS-829, with low-range nanomolar activities. The co-crystallographic structure, surface plasmon resonance binding assay, and cell-based phenotypic nuclear export functional assay validated that exportin-1 is a key target of LFS-829. Moreover, we demonstrated that the C528S mutation or the knockdown on exportin-1 can abolish the cellular activities of LFS-829. Strikingly, oral administration of LFS-829 can significantly reverse the pathological features of colitis model mice. We revealed that LFS-829 can attenuate dual NF-κB signaling and the Nrf2 cytoprotection pathway via targeting exportin-1 in colitis mice. Moreover, LFS-829 has a very low risk of cardiotoxicity and acute toxicity. Therefore, LFS-829 holds great promise for the treatment of colitis and may warrant translation for use in clinical trials.

A20 attenuates hypoxia-induced pulmonary arterial hypertension by inhibiting NF-κB activation and pulmonary artery smooth muscle cell proliferation

PAH is a progressive disease characterized by uncontrolled proliferation of PASMCs. Zinc finger protein A20 is a negative feedback regulatory protein of NF-κB activity. The aim of this study was to evaluate zinc finger protein A20 can alleviate PAH in hypoxia exposed mice. C57BL/6 mice received a tail vein injection of adenovirus-mediated ad-A20 and ad-A20 shRNA were exposed to hypoxia. PASMCs isolated from rat pulmonary arteries were cultured in hypoxia, and were transfection of A20 adenovirus. Pulmonary hemodynamic parameters were measured by right heart catheterization. Pulmonary vascular morphological changes were analyzed by HE and α-SMA staining. The expression changes of A20, NF-κB and its downstream protein were detected. The expression of phospho-p65 was increased with the prolongation of hypoxia time. The expression of A20 in lung tissue of chronic hypoxia group decreased with the prolongation of hypoxia time. Adenovirus-mediated A20 (ad-A20) overexpression significantly attenuated the abnormally increased RVSP, RV/(LV + S) ratio, WT%, WA%, α-SMA and the pulmonary vessel muscularization. Ad-A20 treatment markedly attenuated the degradation of phospho-p65 and inhibited the induction of phospho-IκBα induced by hypoxia treatment. Furthermore, silencing A20 abolished the protection by anti-inflammatory activity and the inhibitory effect on cell proliferation. We showed that Zinc finger protein A20 can block NF-κB signaling pathway, alleviates the hypoxia-induced abnormal elevation of pulmonary arterial pressure, hyperproliferation of PASMCs and the pulmonary vascular remodeling.

Microfluidic platform enables live-cell imaging of signaling and transcription combined with multiplexed secretion measurements in the same single cells

Innate immune cells, including macrophages and dendritic cells, protect the host from pathogenic assaults in part through secretion of a program of cytokines and chemokines (C/Cs). Cell-to-cell variability in C/C secretion appears to contribute to the regulation of the immune response, but the sources of secretion variability are largely unknown. To begin to track the biological sources that control secretion variability, we developed and validated a microfluidic device to integrate live-cell imaging of fluorescent reporter proteins with a single-cell assay of protein secretion. We used this device to image NF-κB RelA nuclear translocation dynamics and Tnf transcription dynamics in macrophages in response to stimulation with the bacterial component lipopolysaccharide (LPS), followed by quantification of secretion of TNF, CCL2, CCL3, and CCL5. We found that the timing of the initial peak of RelA signaling in part determined the relative level of TNF and CCL3 secretion, but not CCL2 and CCL5 secretion. Our results support evidence that differences in timing across cell processes partly account for cell-to-cell variability in downstream responses, but that other factors introduce variability at each biological step.