Negative regulation of NF-κB p65 activity by serine 536 phosphorylation

The effects of luteolin on orthodontic tooth movement and relapse

INTRODUCTION

Luteolin is a natural flavonoid compound that widely exists in human food. Studies have demonstrated luteolin has powerful anti-inflammatory properties and can affect bone remodeling in an inflammatory environment. This study aimed to investigate the effect of luteolin on orthodontic tooth movement (OTM) and relapse after OTM.

METHODS

Male Sprague Dawley rats were randomly divided into 3 groups (n = 8): OTM, 50 mg/kg/d luteolin, and 100 mg/kg/d luteolin. Then, 50 g of orthodontic force was applied to all animals. A saline solution or corresponding concentration of luteolin was given orally. For the OTM experiment, after 14 days of force application, rats were killed, the maxilla was dissected, and then microcomputed tomography, histologic staining, and western blotting were performed. For the relapse experiment, the spring was removed, and a silicone impression was made to record the relapse status.

RESULTS

Compared with the OTM alone group, systemic administration of luteolin inhibited OTM and tooth relapse (P <0.05). Increased bone volume, reduced osteoclast activity, and a decrease in osteoclastogenesis-related protein expression were observed in luteolin-treated groups. These effects may be attributed to the inhibition of the nuclear factor-kappa B pathway.

CONCLUSIONS

Luteolin can significantly inhibit OTM and relapse after OTM. Thus, luteolin is a prospective candidate for enhancing tooth anchorage and preventing relapse in orthodontic treatment.

Non-cyclic nucleotide EPAC1 activators suppress lipopolysaccharide-regulated gene expression, signalling and intracellular communication in differentiated macrophage-like THP-1 cells

This study explores the anti-inflammatory effects of non-cyclic nucleotide EPAC1 activators, PW0577 and SY007, on lipopolysaccharide (LPS)-induced responses in differentiated THP-1 macrophage-like cells. Both activators were found to selectively activate EPAC1 in THP-1 macrophages, leading to the activation of the key down-stream effector, Rap1. RNA sequencing analysis of LPS-stimulated THP-1 macrophages, revealed that treatment with PW0577 or SY007 significantly modulates gene expression related to fibrosis and inflammation, including the suppression of NLRP3, IL-1β, and caspase 1 protein expression in LPS-stimulated cells. Notably, these effects were independent of p65 NFκB phosphorylation at Serine 536, indicating a distinct mechanism of action. The study further identified a shared influence of both activators on LPS signalling pathways, particularly impacting extracellular matrix (ECM) components and NFκB-regulated genes. Additionally, in a co-culture model involving THP-1 macrophages, vascular smooth muscle cells, and human coronary artery endothelial cells, EPAC1 activators modulated immune-vascular interactions, suggesting a broader role in regulating cellular communication between macrophages and endothelial cells. These findings enhance our understanding of EPAC1's role in inflammation and propose EPAC1 activators as potential therapeutic agents for treating inflammatory and fibrotic conditions through targeted modulation of Rap1 and associated signalling pathways.

The effects of acetylated cordycepin derivatives on promoting vascular angiogenesis and attenuating myocardial ischemic injury

Background

Enhanced angiogenesis following myocardial infarction (MI) is beneficial to preserve cardiac function. The present study aimed to investigate whether acetylated derivatives of cordycepin altered its original antitumor properties and exerted cardioprotective effects by promoting angiogenesis in vitro and in vivo.

Methods

Cordycepin and its derivatives with single (DA), double (DAA), and triple acetyl groups (DAAA) were assessed. The cell viability of leukemia U937 cells, malignant hepatoma Huh-7 cells, and human umbilical vascular endothelial cells (HUVECs) treated with cordycepin, DA, DAA, and DAAA were determined. The expression of β-catenin in U937 cells, as well as the expression of p65, p38 and other related signal regulators in HUVECs elicited by lipopolysaccharides (LPS) were also observed. Angiogenesis was determined by tube formation in HUVECs and Matrigel plug assay in mice. Cardiac function following administration of DAAA was evaluated in mice MI model simulated by coronary artery ligation.

Results

The inhibitory effects of cordycepin and its acetylated derivatives on U937 cells, Huh-7 cells, HUVECs, and the expression of β-catenin in U937 cells were mitigated with increasing acetylation. Intriguingly, DAAA preserved the cell viability of HUVECs compared to other acetylated derivatives. Although DAAA had a significantly diminished antitumor effect compared to cordycepin, it promoted angiogenesis in mice and tube formation in HUVECs and attenuated LPS-induced phosphorylation of p65 and p38. Additionally, administration of DAAA improved cardiac function following coronary artery ligation in mice.

Conclusion

DAAA could be considered a promising adjunctive therapy to prevent post-MI heart failure through promoting angiogenesis.

Folic Acid Attenuates N-Methyl-N'-Nitro-N-NitrosoguanidineInduced Gastric Mucosal Injury in Rats

Background/Aims

N-Methyl-N'-nitroso-N-nitrosoguanidine (MNNG) is suspected to increase the risk of developing stomach cancer. Folic acid (FA) is familiar with decreasing inflammation. We expected that FA would protect against MNNG-induced gastric mucosal injury.

Materials and Methods

Thirty 12-week-old SPF-grade female Sprague-Dawley (SD) rats were treated with MNNG and given different dosages of FA as an intervention measure. Quantitative polymerase chain reaction (qPCR) was used to analyze the expression of IL-1, IL-6, IL-8, IL-18, TNF-α, NLRP3, ASC, and caspase-1 genes. The enzyme-linked immunosorbent assay (ELISA) was utilized for the identification of inflammatory cytokines. Western blot was accustomed to detecting IL-1β, IL-18, and NLRP3 inflammatory vesicles in gastric tissue. Furthermore, the gastric mucosal tissues underwent histological examination.

Results

Our investigation demonstrated that FA reduced MNNG-induced inflammatory factor increase by decreasing NF-κB signaling (P < .05). Furthermore, FA prevented the MNNG-induced upregulation of NLRP3 inflammasome-related genes and proteins (all P < .01).

Conclusion

Our data imply that MNNG exposure stimulates the NF-κB/NLRP3 pathway, while FA suppresses it, limiting stomach mucosal inflammation.

Urolithin A promotes atherosclerotic plaque stability by limiting inflammation and hypercholesteremia in Apolipoprotein E-deficient mice

Urolithin A (UroA), a dietary phytochemical, is produced by gut bacteria from fruits rich in natural polyphenols ellagitannins (ETs). The efficiency of ETs metabolism to UroA in humans depends on gut microbiota. UroA has shown a variety of pharmacological activities. In this study we investigated the effects of UroA on atherosclerotic lesion development and stability. Apolipoprotein E-deficient (ApoE-/-) mice were fed a high-fat and high-cholesterol diet for 3 months to establish atherosclerosis model. Meanwhile the mice were administered UroA (50 mg·kg-1·d-1, i.g.). We showed that UroA administration significantly decreased diet-induced atherosclerotic lesions in brachiocephalic arteries, macrophage content in plaques, expression of endothelial adhesion molecules, intraplaque hemorrhage and size of necrotic core, while increased the expression of smooth muscle actin and the thickness of fibrous cap, implying features of plaque stabilization. The underlying mechanisms were elucidated using TNF-α-stimulated human endothelial cells. Pretreatment with UroA (10, 25, 50 μM) dose-dependently inhibited TNF-α-induced endothelial cell activation and monocyte adhesion. However, the anti-inflammatory effects of UroA in TNF-α-stimulated human umbilical vein endothelial cells (HUVECs) were independent of NF-κB p65 pathway. We conducted RNA-sequencing profiling analysis to identify the differential expression of genes (DEGs) associated with vascular function, inflammatory responses, cell adhesion and thrombosis in UroA-pretreated HUVECs. Human disease enrichment analysis revealed that the DEGs were significantly correlated with cardiovascular diseases. We demonstrated that UroA pretreatment mitigated endothelial inflammation by promoting NO production and decreasing YAP/TAZ protein expression and TEAD transcriptional activity in TNF-α-stimulated HUVECs. On the other hand, we found that UroA administration modulated the transcription and cleavage of lipogenic transcription factors SREBP1/2 in the liver to ameliorate cholesterol metabolism in ApoE-/- mice. This study provides an experimental basis for new dietary therapeutic option to prevent atherosclerosis.

Activation of NF-κB signaling regulates ovariectomy-induced bone loss and weight gain

Postmenopausal women experience bone loss and weight gain. To date, crosstalk between estrogen receptor signals and nuclear factor-κB (NF-κB) has been reported, and estrogen depletion enhances bone resorption by osteoclasts via NF-κB activation. However, it is unclear when and in which tissues NF-κB is activated after menopause, and how NF-κB acts as a common signaling molecule for postmenopausal weight gain and bone loss. Therefore, we examined the role of NF-κB in bone and energy metabolism following menopause. NF-κB reporter mice, which can be used to measure NF-κB activation in vivo, were ovariectomized (OVX) and the luminescence intensity after OVX increased in the metaphyses of the long bones and perigonadal white adipose tissue, but not in the other tissues. OVX was performed on wild-type (WT) and p65 mutant knock-in (S534A) mice, whose mutation enhances the transcriptional activity of NF-κB. Weight gain with worsening glucose tolerance was significant in S534A mice after OVX compared with those of WT mice. The bone density of the sham group in WT or S534A mice did not change, whereas in the S534A-OVX group it significantly decreased due to the suppression of bone formation and increase in bone marrow adipocytes. Disulfiram, an anti-alcoholic drug, suppressed OVX-induced activation of NF-κB in the metaphyses of long bones and white adipose tissue (WAT), as well as weight gain and bone loss. Overall, the activation of NF-κB in the metaphyses of long bones and WAT after OVX regulates post-OVX weight gain and bone loss.

Activation of the NLRP1B inflammasome by caspase-8

Cleavage of the innate immune receptor NLRP1B by various microbial proteases causes the proteasomal degradation of its N-terminal fragment and the subsequent release of a C-terminal fragment that forms an inflammasome. We reported previously that metabolic stress caused by intracellular bacteria triggers NLRP1B activation, but the mechanism by which this occurs was not elucidated. Here we demonstrate that TLR4 signaling in metabolically stressed macrophages promotes the formation of a TRIF/RIPK1/caspase-8 complex. Caspase-8 activity, induced downstream of this TLR4 pathway or through a distinct TNF receptor pathway, causes cleavage and activation of NLRP1B, which facilitates the maturation of both pro-caspase-1 and pro-caspase-8. Thus, our findings indicate that caspase-8 and NLRP1B generate a positive feedback loop that amplifies cell death processes and promotes a pro-inflammatory response through caspase-1. The ability of NLRP1B to detect caspase-8 activity suggests that this pattern recognition receptor may play a role in the defense against a variety of pathogens that induce apoptosis.

Phosphorylation of Serine 536 of p65(RelA) Downregulates Inflammatory Responses

Nuclear factor-κB (NF-κB) is a transcription factor that regulates the expression of various genes involved in inflammatory diseases and immune responses. Recently, a novel transcriptional regulatory mechanism of NF-κB involving the phosphorylation of serine 536 (534 in mice; S534) of its p65 subunit was reported; however, further research is required to elucidate the physiological role of S534 phosphorylation. Therefore, we generated S534A knock-in (KI) mice, in which the S534 of p65 was substituted with alanine. Similar to the wild-type (WT) mice, S534A KI mice developed normally. After stimulation with tumor necrosis factor α (TNFα), mouse embryonic fibroblasts (MEFs) derived from S534A KI mice exhibited increased target gene expression compared with that in the WT MEFs, which was induced by long-term binding of p65 to DNA. According to comprehensive gene expression analysis after stimulation with TNFα, the expression of genes p65ted to inflammatory and immune responses was increased, and the expression of genes p65ted to lipolysis was decreased in S534A KI MEFs. Analyses of a periodontal disease model established using WT and S534A KI mice revealed that alveolar bone resorption was enhanced in S534A KI mice owing to an increase in the number of osteoclasts, which was not attributed to the differentiation of osteoclast precursor cells but to an increased expression of interleukin-1β and receptor activator of NF-κB ligand in the periodontal tissue. Hence, phosphorylation of S536 negatively regulates inflammatory responses in vitro and in vivo.

IKKε-deficient macrophages impede cardiac repair after myocardial infarction by enhancing the macrophage-myofibroblast transition

The regulatory role of the inhibitor of NF-kB kinase ε (IKKε) in postmyocardial infarction (MI) inflammation remains uncertain. Using an MI mouse model, we examined the cardiac outcomes of IKKε knockout (KO) mice and wild-type mice. We employed single-cell RNA sequencing (scRNA-seq) and phosphorylated protein array techniques to profile cardiac macrophages. IKKε KO mice exhibited compromised survival, heightened inflammation, pronounced cardiac fibrosis, and a reduced ejection fraction. A distinct cardiac macrophage subset in IKKε KO mice exhibited increased fibrotic marker expression and decreased phosphorylated p38 (p-p38) levels, indicating an enhanced macrophage-myofibroblast transition (MMT) post-MI. While cardiac inflammation is crucial for initiating compensatory pathways, the timely resolution of inflammation was impaired in the IKKε KO group, while the MMT in macrophages accelerated post-MI, leading to cardiac failure. Additionally, our study highlighted the potential of 5-azacytidine (5-Aza), known for its anti-inflammatory and cardioprotective effects, in restoring p-p38 levels in stimulated macrophages. The administration of 5-Aza significantly reduced the MMT in cardiac macrophages from the IKKε KO group. These findings underscore the regulation of the inflammatory response and macrophage transition by the IKKε-p38 axis, indicating that the MMT is a promising therapeutic target for ischemic heart disease.

Nutritional, antioxidant and biological activity characterization of orange peel flour to produce nutraceutical gluten-free muffins

Celiac disease - a prevalent food intolerance - requires strict adherence to a lifelong gluten-free (GF) diet as the only effective treatment. However, GF products often lack soluble fibre and have a high glycaemic index. Consequently, there is a pressing need in the food industry to develop GF products with improved nutritional profiles. In this context, the impact of incorporating orange peel flour (OPF) into muffins undergoing sourdough fermentation was examined, focusing on their technological, antioxidant, and nutritional characteristics. The functional properties of OPF were investigated using human colon carcinoma HCT8 cells as a model system. Treatment with OPF extract demonstrated a notable reduction in malignant cell viability and intracellular ROS levels, indicating potent antioxidant capabilities. Western blot analysis revealed significant alterations in key signalling pathways, including increased phosphorylation of NF-kB at serine 536 and reduced intracellular levels of caspase-3, alongside increased phosphorylation of RIPK3 and MLKL, suggesting potential involvement in necroptosis. OPF incorporation in muffins with sourdough increased antioxidant activity, reduced glycaemic index, and affected the volatile profile. Furthermore, based on simulated colonic fermentation, muffins with OPF showed a slight prebiotic effect, supported by the significant increase in bacillus-shaped lactic acid bacteria and Clostridia population. Overall, OPF-enriched muffins demonstrated considerable antioxidant effects and impacts on cell viability, underscoring their potential as functional ingredients in GF products. These findings signify the prospect of OPF enhancing the nutritional profiles and conferring health benefits of GF muffins.

Melatonin Protects Against Colistin-Induced Intestinal Inflammation and Microbiota Dysbiosis

Colistin is renowned as a last-resort antibiotic due to the emergence of multidrug-resistant pathogens. However, its potential toxicity significantly hampers its clinical utilization. Melatonin, chemically known as N-acetyl-5-hydroxytryptamine, is an endogenous hormone produced by the pineal gland and possesses diverse biological functions. However, the protective role of melatonin in alleviating antibiotic-induced intestinal inflammation remains unknown. Herein, we reveal that colistin stimulation markedly elevates intestinal inflammatory levels and compromises the gut barrier. In contrast, pretreatment with melatonin safeguards mice against intestinal inflammation and mucosal damage. Microbial diversity analysis indicates that melatonin supplementation prevents a reduction in the abundance of Erysipelotrichales and Bifidobacteriales, as well as an increase in Desulfovibrionales abundance, following colistin exposure. Remarkably, short-chain fatty acids (SCFAs) analysis shows that propanoic acid contributes to the protective effect of melatonin on colistin-induced intestinal inflammation. Furthermore, the protection effects of melatonin and propanoic acid on LPS-induced cellular inflammation in RAW 264.7 cells are confirmed. Mechanistic investigations suggest that intervention with melatonin and propanoic acid can repress the activation of the TLR4 signal and its downstream NF-κB and MAPK signaling pathways, thereby mitigating the toxic effects of colistin. Our work highlights the unappreciated role of melatonin in preventing the potential detrimental effects of colistin on intestinal health and suggests a combined therapeutic strategy to effectively manage intestinal infectious diseases.

Ferritin Light Chain Alleviates Cerebral Ischemic-Reperfusion Injury-Induced Neuroinflammation via the HIF1α Mediated NF-κB Signaling Pathways

Ferritin light chain (FtL) is a complex formed by apoferritin and iron core and is one of the main storage forms of iron. Currently, the precise role of FtL in cerebral ischemia/reperfusion injury (CIRI) remains undetermined. This investigation aimed to elucidate the roles and underlying mechanisms of FtL in CIRI. To induce CIRI, an oxygen-glucose deprivation (OGD) model in microglia and middle cerebral artery occlusion (MCAO) model were established using C57BL/6 J mice. The in vivo and in vitro FtL expression patterns were assessed. Furthermore, the potential regulatory mechanism of FtL at the upstream level was also explored. In addition, the in vivo and in vitro role of FtL in post-ischemic inflammation was also clarified. The results indicated that FtL was up-regulated in OGD-induced microglia and CIRI mice. Moreover, OGD activated HIF1α, which interacted with the FtL promoter region as an activator, thereby increasing FtL expression. Furthermore, FtL attenuated the release of pro-inflammatory cytokines (TNFα, IL6) and decreased levels of COX2 and iNOS in microglia; however, FtL knockdown had the opposite effects. Up-regulated FtL was observed to inhibit OGD-induced NF-κB activation in microglia, decreased IκBα degradation, and reduced NF-κB/p65 nuclear translocation. In summary, this study revealed an underlying mechanism of FtL upregulation via HIF1α and highlighted its protective role against post-ischemic neuroinflammation, indicating the potential of FtL as a target for CIRI treatment.

Sphinganine recruits TLR4 adaptors in macrophages and promotes inflammation in murine models of sepsis and melanoma

After recognizing its ligand lipopolysaccharide, Toll-like receptor 4 (TLR4) recruits adaptor proteins to the cell membrane, thereby initiating downstream signaling and triggering inflammation. Whether this recruitment of adaptor proteins is dependent solely on protein-protein interactions is unknown. Here, we report that the sphingolipid sphinganine physically interacts with the adaptor proteins MyD88 and TIRAP and promotes MyD88 recruitment in macrophages. Myeloid cell-specific deficiency in serine palmitoyltransferase long chain base subunit 2, which encodes the key enzyme catalyzing sphingolipid biosynthesis, decreases the membrane recruitment of MyD88 and inhibits inflammatory responses in in vitro bone marrow-derived macrophage and in vivo sepsis models. In a melanoma mouse model, serine palmitoyltransferase long chain base subunit 2 deficiency decreases anti-tumor myeloid cell responses and increases tumor growth. Therefore, sphinganine biosynthesis is required for the initiation of TLR4 signal transduction and serves as a checkpoint for macrophage pattern recognition in sepsis and melanoma mouse models.

Post-translational modifications of p65: state of the art

P65, a protein subunit of NF-κB, is a widely distributed transcription factor in eukaryotic cells and exerts diverse regulatory functions. Post-translational modifications such as phosphorylation, acetylation, methylation and ubiquitination modulate p65 transcriptional activity and function, impacting various physiological and pathological processes including inflammation, immune response, cell death, proliferation, differentiation and tumorigenesis. The intricate interplay between these modifications can be antagonistic or synergistic. Understanding p65 post-translational modifications not only elucidates NF-κB pathway regulation but also facilitates the identification of therapeutic targets and diagnostic markers for associated clinical conditions.

Caspase-4 promotes metastasis and interferon-γ-induced pyroptosis in lung adenocarcinoma

Caspase-4 (CASP4) is a member of the inflammatory caspase subfamily and promotes inflammation. Here, we report that CASP4 in lung adenocarcinoma cells contributes to both tumor progression via angiogenesis and tumor hyperkinesis and tumor cell killing in response to high interferon (IFN)-γ levels. We observe that elevated CASP4 expression in the primary tumor is associated with cancer progression in patients with lung adenocarcinoma. Further, CASP4 knockout attenuates tumor angiogenesis and metastasis in subcutaneous tumor mouse models. CASP4 enhances the expression of genes associated with angiogenesis and cell migration in lung adenocarcinoma cell lines through nuclear factor kappa-light chain-enhancer of activated B cell signaling without stimulation by lipopolysaccharide or tumor necrosis factor. CASP4 is induced by endoplasmic reticulum stress or IFN-γ via signal transducer and activator of transcription 1. Most notably, lung adenocarcinoma cells with high CASP4 expression are more prone to IFN-γ-induced pyroptosis than those with low CASP4 expression. Our findings indicate that the CASP4 level in primary lung adenocarcinoma can predict metastasis and responsiveness to high-dose IFN-γ therapy due to cancer cell pyroptosis.

Xuanfu Daizhe Tang alleviates reflux esophagitis in rats by inhibiting the STAT1/TREM-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Reflux esophagitis (RE) is a common chronic inflammatory disease of the esophageal mucosa with a high prevalence and recurrence rate, for which a satisfactory therapeutic strategy is still lacking. Chinese medicine has its characteristics and advantages in treating RE, and the clinical application of Xuanfu Daizhe Tang (XDT) in treating RE has achieved sound therapeutic effects. However, there needs to be more research on its mechanism of action.

AIM OF THE STUDY

The present work aimed to investigate the mechanism of XDT action in RE through the Signal Transducer and Activator of Transcription 1 (STAT1)/Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) pathway.

MATERIALS AND METHODS

The main active components of XDT were analyzed by ultra-performance liquid chromatography-mass spectrometer (UPLC-MS). The effect of XDT on RE was evaluated in a rat model of RE induced by "Cardioplasty + pyloric ligation + Roux-en-Y esophagojejunostomy". Each administration group was treated by gavage. The degree of damage to the esophageal mucosa was evaluated by visual observation, and the Potential of Hydrogen (PH) method and Hematoxylin-eosin staining (HE) staining were performed. Serum levels of Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Tumor Necrosis Factor alpha (TNF-α), and Inducible Nitric Oxide Synthase (iNOS) were measured by ELISA. Quantitative Real-time PCR (qPCR), Western Blot (WB), and Immunofluorescence (IF) methods were used to detect Claudin-4, Claudin-5, TREM-1, and p-STAT1 in esophageal tissues for studying the mechanism of action and signaling pathway of XDT. Immunohistochemistry (IHC) analysis was used to detect the expression of TREM-1 and CD68 in esophageal tissues. Flow Cytometry (FC) was used to detect the polarization of macrophages in the blood. After conducting preliminary experiments to verify our hypothesis, we performed molecular docking between the active component of XDT and STAT1 derived from rats and parallel experiments with STAT1 inhibitor. The selective increaser of STAT1 transcription (2-NP) group was used to validate the mechanism by which XDT acts.

RESULTS

XDT alleviated esophageal injury and attenuated histopathological changes in RE rats. XDT also inhibited the inflammatory response and decreased serum IL-1β, IL-6, TNF-α, and iNOS levels in RE rats. qPCR and WB results revealed that XDT inhibited the expression of Claudin-4, Claudin-5, TREM-1, and STAT1 in the esophageal mucosa of RE rats. IHC and FC results showed that XDT reduced TREM-1 levels in esophageal tissues and polarized macrophages toward M2. The molecular docking results showed that rat-derived STAT1 can strongly bind to Isochronogenic acid A in XDT. The parallel experimental results of STAT1 inhibitor showed that XDT has anti-inflammatory effects similar to STAT1 inhibitors. The 2-NP group confirmed that XDT exerts its therapeutic effect on reflux esophagitis through the STAT1/TREM-1 pathway, with STAT1 as the upstream protein.

CONCLUSIONS

This study suggests that XDT may treat reflux esophagitis by modulating the STAT1/TREM-1 pathway.

Inhibition of NF-κB-Mediated Proinflammatory Transcription by Ru(II) Complexes of Anti-Angiogenic Ligands in Triple-Negative Breast Cancer

Nuclear factor kappa beta (NF-κB) plays a pivotal role in breast cancer, particularly triple-negative breast cancer, by promoting inflammation, proliferation, epithelial-mesenchymal transition, metastasis, and drug resistance. Upregulation of NF-κB boosts vascular endothelial growth factor (VEGF) expression, assisting angiogenesis. The Ru(II) complexes of methyl- and dimethylpyrazolyl-benzimidazole N,N donors inhibit phosphorylation of ser536 in p65 and translocation of the NF-κB heterodimer (p50/p65) to the nucleus, disabling transcription to upregulate inflammatory signaling. The methyl- and dimethylpyrazolyl-benzimidazole inhibit VEGFR2 phosphorylation at Y1175, disrupting downstream signaling through PLC-γ and ERK1/2, ultimately suppressing Ca(II)-signaling. Partial release of the antiangiogenic ligand in a reactive oxygen species-rich environment is possible as per our observation to inhibit both NF-κB and VEGFR2 by the complexes. The complexes are nontoxic to zebrafish embryos up to 50 μM, but the ligands show strong in vivo antiangiogenic activity at 3 μM during embryonic growth in Tg(fli1:GFP) zebrafish but no visible effect on the adult phase.

FASN negatively regulates p65 expression by reducing its stability via Thr254 phosphorylation and isomerization by Pin1

FASN, the sole cytosolic enzyme responsible for de novo palmitate synthesis in mammalian cells, has been associated with poor prognosis in cancer and shown to cause drug and radiation resistance by upregulating DNA damage repair via suppression of p65 expression. Targeting FASN by repurposing proton pump inhibitors has generated impressive outcomes in triple-negative breast cancer patients. While p65 regulation of DNA damage repair was thought to be due to its suppression of poly(ADP-ribose) polymerase 1 gene transcription, the mechanism of FASN regulation of p65 expression was unknown. In this study, we show that FASN regulates p65 stability by controlling its phosphorylation at Thr254, which recruits the peptidyl-prolyl cis/trans isomerase Pin1 that is known to stabilize many proteins in the nucleus. This regulation is mediated by palmitate, the FASN catalytic product, not by FASN protein per se. This finding of FASN regulation of p65 stability via phosphorylation of Thr254 and isomerization by Pin1 implicates that FASN and its catalytic product palmitate may play an important role in regulating protein stability in general and p65 more specifically.

Innate Immune-Enhancing Effect of Pinus densiflora Pollen Extract via NF-κB Pathway Activation

Considering the emergence of various infectious diseases, including the coronavirus disease 2019 (COVID-19), people's attention has shifted towards immune health. Consequently, immune-enhancing functional foods have been increasingly consumed. Hence, developing new immune-enhancing functional food products is needed. Pinus densiflora pollen can be collected from the male red pine tree, which is commonly found in Korea. P. densiflora pollen extract (PDE), obtained by water extraction, contained polyphenols (216.29 ± 0.22 mg GAE/100 g) and flavonoids (35.14 ± 0.04 mg CE/100 g). PDE significantly increased the production of nitric oxide (NO) and reactive oxygen species (ROS) but, did not exhibit cytotoxicity in RAW 264.7 cells. Western blot results indicated that PDE induced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2. PDE also significantly increased the mRNA and protein levels of cytokines and the phosphorylation of IKKα/β and p65, as well as the activation and degradation of IκBα. Additionally, western blot analysis of cytosolic and nuclear fractions and immunofluorescence assay confirmed that the translocation of p65 to the nucleus after PDE treatment. These results confirmed that PDE increases the production of cytokines, NO, and ROS by activating NF-κB. Therefore, PDE is a promising nutraceutical candidate for immune-enhancing functional foods.

Tianhuang formula ameliorates liver fibrosis by inhibiting CCL2-CCR2 axis and MAPK/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

In the progression of chronic liver diseases, liver fibrosis is a reversible pathophysiologic event for liver diseases prognosis and risk of cirrhosis. Liver injury factors of different etiologies mediate this process. There is still a lack of effective medications for treating liver fibrosis. Additionally, the ameliorative effects of traditional herbs on liver fibrosis have been commonly reported. Tianhuang formula (THF) is a drug combination consisting of 2 traditional Chinese herbs, which has been showing significant improvement in metabolic liver diseases. However, the hepatoprotective effect and mechanism of THF in ameliorating liver fibrosis are still unclear.

AIM OF THE STUDY

This study aimed to investigate the effects of THF on carbon tetrachloride (CCl4)-induced and methionine-choline-deficient (MCD) diet-induced liver fibrosis model and to reveal the potential mechanisms. It can provide experimental evidence for THF as a therapeutic candidate for liver fibrosis.

MATERIALS AND METHODS

In this study, CCl4-induced mice were treated with THF (80 mg/kg, 160 mg/kg) or Fuzheng Huayu (FZHY) capsules (4.8 g/kg) for 6 weeks. MCD-induced mice received the same doses of THF or FZHY for 4 weeks. FZHY is used as a comparative study in these two models. Following that, using kit reagents detected changes in relevant serum and liver biochemical indicators. Histological changes in mouse liver were measured by staining of H&E and Sirius Red. The markers expression of liver fibrosis and inflammation were detected using qRT-PCR, western blotting and immunohistochemical staining analysis. The potential regulatory mechanism of THF to ameliorate liver fibrosis was performed by RNA-sequencing analysis. Finally, the analysis results were verified by immunofluorescence co-staining, qRT-PCR and western blotting.

RESULTS

Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic triglyceride (TG) levels in CCl4 and MCD-induced liver fibrosis mice were significantly improved after THF treatment. Meanwhile, the expression of fibrosis and inflammation markers were significantly suppressed. Furthermore, THF downregulated the expression of the macrophage marker CD68. According to RNA-sequencing analysis, we found the CCL2-CCR2 axis and MAPK/NF-κB as the potential signaling pathway for THF against liver fibrosis.

CONCLUSION

This study revealed that THF ameliorated liver injury, inflammation and fibrotic process by inhibiting CCL2-CCR2 axis and its downstream MAPK/NF-κB signaling pathway.

Role of the ubiquitin-proteasome system in the sarcopenic-like phenotype induced by CCL5/RANTES

Sarcopenia is characterized by reduced muscle strength and mass and a decline in muscle fiber diameter and amount of sarcomeric proteins. Sarcopenia involves the activation of the ubiquitin-proteasome system (UPS). MuRF-1 and atrogin-1 are E3 ubiquitin ligases belonging to UPS, leading to proteolysis mediated by the PSMB 5, 6, and 7 subunits of 20S proteasome. CCL5/RANTES induces a sarcopenic-like effect in muscle cells. The present work explored the impact of CCL5 on UPS components and the influence of UPS on its sarcopenic-like effect. We demonstrated that CCL5 increased MuRF-1 and atrogin-1 protein levels and mRNA levels of subunits PSMB 5, 6, and 7. We used the MG132 inhibitor to elucidate the role of the 20S proteasome in the CCL5-induced sarcopenic-like effect. This inhibitor prevented the decrease in troponin and MHC protein levels and partially prevented the reduction in the diameter of single-isolated FDB muscle fibers induced by CCL5. These findings indicate that CCL5 actively modulates the UPS. Moreover, our results show the direct participation of UPS in the sarcopenic-like phenotype induced by CCL5.

Interplay between SUMO1-related SUMOylation and phosphorylation of p65 promotes hepatocellular carcinoma progression

The nuclear factor kappaB (NF-κB) subunit p65, plays an important role in the progression of hepatocellular carcinoma (HCC). Phosphorylation of p65 is considered as an important mechanism for the positive regulation of NF-κB activity. According to our previous data, p65 can be SUMOylated by small ubiquitin-related modifier 1 (SUMO1) protein, and SUMO1 promotes p65 nuclear import and HCC progression. However, the effect of SUMO1-related p65 SUMOylation on NF-κB transcriptional activity and the relationship between phosphorylation and SUMOylation of p65 remain obscure. Here, we found that phosphorylated p65 level was increased in cancer tissues of HCC patients, and similar phenomenon was found for SUMO1 expression but not for SUMO2/3. Further clinical data showed a positive correlation between SUMO1 and phosphorylated p65. We also verified that overexpression of SUMO1 upregulated phosphorylated p65 levels. Next, we verified SUMO1-related p65 SUMOylation with in vitro SUMOylation assay, constructed mutants of p65 SUMOylation and phosphorylation, and found that SUMO1-related p65 SUMOylation promoted p65 nuclear import and increased NF-κB activity. Both SUMO1-related p65 SUMOylation and p65 phosphorylation (especially at S276 site) increased the viability and invasion of hepatoma cells, and decreased the apoptosis of hepatoma cells. At last, we found that the phosphorylation of p65 promoted the level of SUMO1-related p65 SUMOylation, and SUMO1-related p65 SUMOylation upregulated phosphorylated p65 (at S276 site). Our study contributes to the exploration of the oncogenic mechanism of p65, which is the important protein in HCC.

Oxoaporphine Pr(III) complex inhibits hepatocellular carcinoma progression and metastasis by disrupting tumor cell-macrophage crosstalk

Tumor cells and macrophages communicate through the secretion of various cytokines to jointly promote the malignant development of cancers. We synthesized and characterized an oxoaporphine Pr(III) complex (PrL3(NO3)3) and found that it inhibits hepatocellular carcinoma (HCC) progression and metastasis by disrupting HCC cell-macrophage crosstalk. PrL3(NO3)3 treatment upregulated CD86, TNF-α, and IL-1β and downregulated CD163, CD206, CCL2, and VEGFA in macrophages. Our mRNA-Seq results demonstrated that PrL3(NO3)3 inhibited macrophage M2-like polarization by inhibiting the AMPK pathway and activating the NF-κB pathway by upregulating RelA/p65 Ser536 phosphorylation. This kind of macrophage polarization significantly inhibited HCC cell proliferation, migration, and invasion. In addition, PrL3(NO3)3 inhibited the migration, invasion, and chemotaxis of HCC cells by downregulating the expression of EMT-related markers and CCL2. hTFtarget database analysis revealed that PrL3(NO3)3 inhibited NF-κB nuclear translocation by upregulating RelA/p65 Ser536 phosphorylation in HCC cells, thereby downregulating the expression of Snail and CCL2. HCC tissue microarray analysis revealed that downregulation of RelA/p65 Ser536 phosphorylation is a driving event in HCC malignant progression. In conclusion, PrL3(NO3)3 effectively inhibits HCC cell-macrophage crosstalk by upregulating RelA/p65 Ser536 phosphorylation. This is the first report of a lanthanide complex exerting regulatory effects on both tumors and tumor-associated macrophages, providing a new strategy for the development of effective antitumor drugs.

Regulation of anti-inflammatory and antioxidant responses by methanol extract of Mikania cordata (Burm. f.) B. L. Rob. leaves via the inactivation of NF-κB and MAPK signaling pathways and activation of Nrf2 in LPS-induced RAW 264.7 macrophages

Mikania cordata (Burm. f.) B.L. Rob. has been traditionally used in tropical countries throughout Asia and Africa to treat gastric ulcers, dyspepsia, and dysentery. However, the mechanisms responsible for its anti-inflammatory and antioxidant activities are not fully understood. Therefore, this study sought to investigate the anti-inflammatory and antioxidant effects of methanol extracts of M. cordata (MMC) on inflammation and oxidative stress in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 macrophages and elucidate its underlying regulatory mechanism. MMC significantly suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated RAW 264.7 macrophages by downregulating the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the mRNA and protein levels. Moreover, MMC effectively reduced the mRNA expression levels and production of pro-inflammatory cytokines, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α (TNF-α). These suppressive effects of MMC on pro-inflammatory mediators and cytokines were mediated through the inhibition of transforming growth factor beta-activated kinase 1 (TAK1), which subsequently blocked the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). MMC also upregulated the nuclear factor erythroid-2-related factor 2 (Nrf2) by inducing the degradation of Kelch-like ECH-related protein 1 (Keap1), an Nrf2-specific E3 ligase. Accordingly, MMC enhanced Nrf2 target gene expression of anti-oxidative regulators such as heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). However, it had minimal effect on the DPPH radical scavenging capacity in vitro. Collectively, these findings demonstrate that MMC holds promise as a potential therapeutic agent for alleviating inflammation-related diseases and oxidative stress.

Secoisolariciresinol diglucoside Ameliorates Osteoarthritis via Nuclear factor-erythroid 2-related factor-2/ nuclear factor kappa B Pathway: In vitro and in vivo experiments

Osteoarthritis (OA) is an age-related joint disease in which inflammation and extracellular matrix (ECM) degradation play a crucial role in the destruction of articular cartilage. Secoisolariciresinol diglucoside (SDG), the main lignan in wholegrain flaxseed, which has been reported to remarkably suppress inflammation and oxidative stress, may have potential therapeutic value in OA. In this study, the effect and mechanism of SDG against cartilage degeneration were verified in the destabilization of the medial meniscus (DMM) and collagen-induced (CIA) arthritis models and interleukin-1β (IL-1β)-stimulated osteoarthritis chondrocyte models. From our experiments, SDG treatment downregulated the expression of pro-inflammatory factors induced by IL-1β in vitro, including inducible nitric oxide synthase (INOS), cyclooxygenase-2 (COX2), tumor necrosis factor (TNF-α), and interleukin 6 (IL-6). Additionally, SDG promoted the expression of collagen II (COL2A1) and SRY-related high-mobility-group-box gene 9(SOX9), while suppressing the expression of a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5) and matrix metalloproteinases 13(MMP13), which leads to catabolism. Consistently, in vivo, SDG has been identified to have chondroprotective effects in DMM-induced and collagen-induced arthritis models. Mechanistically, SDG exerted its anti-inflammation and anti-ECM degradation effects by activating the Nrf2/HO-1 pathway and inhibiting the nuclear factor kappa B (NF-κB) pathway. In conclusion, SDG ameliorates the progression of OA via the Nrf2/NF-κB pathway, which indicates that SDG may have therapeutic potential for OA.

New Insights into NF-κB Signaling in Innate Immunity: Focus on Immunometabolic Crosstalks

The nuclear factor kappa B (NF-κB) is a family of transcription factors that, beyond their numberless functions in various cell processes, play a pivotal role in regulating immune cell activation. Two main pathways-canonical and non-canonical-are responsible for NF-κB activation and heterodimer translocation into the nucleus. A complex crosstalk between NF-κB signaling and metabolism is emerging in innate immunity. Metabolic enzymes and metabolites regulate NF-κB activity in many cases through post-translational modifications such as acetylation and phosphorylation. On the other hand, NF-κB affects immunometabolic pathways, including the citrate pathway, thereby building an intricate network. In this review, the emerging findings about NF-κB function in innate immunity and the interplay between NF-κB and immunometabolism have been discussed. These outcomes allow for a deeper comprehension of the molecular mechanisms underlying NF-κB function in innate immune cells. Moreover, the new insights are important in order to perceive NF-κB signaling as a potential therapeutic target for inflammatory/immune chronic diseases.

Schizandrin C regulates lipid metabolism and inflammation in liver fibrosis by NF-κB and p38/ERK MAPK signaling pathways

Liver fibrosis is considered a sustained wound healing response and metabolic syndrome, and its therapy is of great significance for chronic liver disease. Schizandrin C, as one lignan from hepatic protectant Schisandra chinensis, can depress the oxidative effect and lipid peroxidation, and protect against liver injury. In this study, C57BL/6J mice were used to estimate a liver fibrosis model by CCl₄, and Schizandrin C exerted an anti-hepatic fibrosis effect, as evidenced by decreased alanine aminotransferase, aspartate aminotransferase and total bilirubin activities in serum, lower hydroxyproline content, recuperative structure and less collagen accumulation in the liver. In addition, Schizandrin C reduced the expressions of alpha-smooth muscle actin and type Ι collagen in the liver. In vitro experiments also revealed that Schizandrin C attenuated hepatic stellate cell activation in both LX-2 and HSC-T6 cells. Furthermore, lipidomics and quantitative real-time PCR analysis revealed that Schizandrin C regulated the lipid profile and related metabolic enzymes in the liver. In addition, the mRNA levels of inflammation factors were downregulated by Schizandrin C treatment, accompanied by lower protein levels of IκB-Kinase-β, nuclear factor kappa-B p65, and phospho-nuclear factor kappa-B p65. Finally, Schizandrin C inhibited the phosphorylation of p38 MAP kinase and extracellular signal-regulated protein kinase, which were activated in the CCl₄ fibrotic liver. Taken together, Schizandrin C can regulate lipid metabolism and inflammation to ameliorate liver fibrosis by nuclear factor kappa-B and p38/ERK MAPK signaling pathways. These findings supported Schizandrin C as a potential drug for liver fibrosis.

Astrocyte reactivity in the glia limitans superficialis of the rat medial prefrontal cortex following sciatic nerve injury

The glia limitans superficialis (GLS) on the rodent cortical surface consists of astrocyte bodies intermingled with their cytoplasmic processes. Many studies have observed astrocyte reactivity in the medial prefrontal cortex (mPFC) parenchyma induced by a peripheral nerve injury, while the response of GLS astrocytes is still not fully understood. The aim of our study was to identify the reactivity of rat GLS astrocytes in response to sciatic nerve compression (SNC) over different time periods. The alteration of GLS astrocyte reactivity was monitored using immunofluorescence (IF) intensities of glial fibrillary acidic protein (GFAP), glutamine synthetase (GS), and NFκBp65. Our results demonstrated that SNC induced GLS astrocyte reactivity seen as increased intensities of GFAP-IF, and longer extensions of cytoplasmic processes into lamina I. First significant increase of GFAP-IF was observed on post-operation day 7 (POD7) after SNC with further increases on POD14 and POD21. In contrast, dynamic alteration of the extension of cytoplasmic processes into lamina I was detected as early as POD1 and continued throughout the monitored survival periods of both sham and SNC operations. The reactivity of GLS astrocytes was not associated with their proliferation. In addition, GLS astrocytes also displayed a significant decrease in GS immunofluorescence (GS-IF) and NFκB immunofluorescence (NFκB-IF) in response to sham and SNC operation compared with naïve control rats. These results suggest that damaged peripheral tissues (following sham operation as well as peripheral nerve lesions) may induce significant changes in GLS astrocyte reactivity. The signaling mechanism from injured peripheral tissue and nerve remains to be elucidated.

Effects of resveratrol and its derivative pterostilbene on hepatic injury and immunological stress of weaned piglets challenged with lipopolysaccharide

The present study was to investigate the protective effects of resveratrol (RSV) and its 3,5-dimethylether derivative pterostilbene (PT) against liver injury and immunological stress of weaned piglets upon lipopolysaccharide (LPS) challenge. Seventy-two weaned piglets were divided into the following groups: control group, LPS-challenged group, and LPS-challenged groups pretreated with either RSV or PT for 14 d (n = 6 pens, three pigs per pen). At the end of the feeding trial, piglets were intraperitoneally injected with either LPS or an equivalent amount of sterile saline. After 6 h of sterile saline or LPS injection, plasma and liver samples were collected. LPS stimulation caused massive apoptosis, activated inflammatory responses, and incited severe oxidative stress in the piglet livers while also promoting the nuclear translocation of nuclear factor kappa B (NF-κB) p65 (P < 0.001) and the protein expression of Nod-like receptor pyrin domain containing 3 (NLRP3; P = 0.001) and cleaved caspase 1 (P < 0.001). PT was more effective than RSV in alleviating LPS-induced hepatic damage by decreasing the apoptotic rate of liver cells (P = 0.045), inhibiting the transcriptional expression of interleukin 1 beta (P < 0.001) and interleukin 6 (P = 0.008), and reducing myeloperoxidase activity (P = 0.010). The LPS-induced increase in hepatic lipid peroxidation accumulation was also reversed by PT (P = 0.024). Importantly, inhibiting protein phosphatase 2A (PP2A) activity in a hepatocellular model largely blocked the ability of PT to prevent tumor necrosis factor alpha-induced increases in NF-κB p65 protein phosphorylation (P = 0.043) and its nuclear translocation (P = 0.029). In summary, PT is a promising agent that may alleviate liver injury and immunological stress of weaned piglets via the PP2A/NF-κB/NLRP3 signaling pathway.

Identification of therapeutic targets in a murine model of severe exertional heat stroke

Exertional heat stroke (EHS) is a potentially lethal condition resulting from high core body temperatures (TC) in combination with a systemic inflammatory response syndrome (SIRS) with varying degrees of severity across victims, and limited understanding of the underlying mechanism(s). We established a mouse model of severe EHS to identify mechanisms of hyperthermia/inflammation that may be responsible for organ damage. Mice were forced to run on a motorized wheel in a 37.5°C chamber until loss of consciousness and were either removed immediately (exertional heat injury or EHI; TCMax = 42.4 ± 0.2°C) or remained in the chamber an additional 20 min (EHS; TCMax = 42.5 ± 0.4°C). Exercise control mice (ExC) experienced identical procedures to EHS at 25°C. At 3 h post-EHS, there was evidence for an immune/inflammatory response as elevated blood chemokine [interferon γ-induced protein 10 (IP-10), keratinocytes-derived chemokine (KC), macrophage inflammatory proteins (MIP-1α), MIP-1β, MIP-2] and cytokine [granulocyte colony-stimulating factor (G-CSF), interleukins (IL-10), IL-6] levels peaked and were highest in EHS mice compared with EHI and ExC mice. Immunoblotting of organs susceptible to EHS damage indicated that several kinases were sensitive to stress associated with heat/inflammation and exercise; specifically, phosphorylation of liver c-Jun NH2-terminal kinase (JNK) at threonine 183/tyrosine 185 immediately (0 h) postheating related to heat illness severity. We have established a mouse EHS model, and JNK [or its downstream target(s)] could underlie EHS symptomatology, allowing the identification of molecular pathways or countermeasure targets to mitigate heat illness severity, enable complete recovery, and decrease overall EHS-related fatalities.

Silencing P2X7R Alleviates Diabetic Neuropathic Pain Involving TRPV1 via PKCε/P38MAPK/NF-κB Signaling Pathway in Rats

Transient receptor potential vanillic acid 1 (TRPV1) is an ion channel activated by heat and inflammatory factors involved in the development of various types of pain. The P2X7 receptor is in the P2X family and is associated with pain mediated by satellite glial cells. There might be some connection between the P2X7 receptor and TRPV1 in neuropathic pain in diabetic rats. A type 2 diabetic neuropathic pain rat model was induced using high glucose and high-fat diet for 4 weeks and low-dose streptozocin (35 mg/kg) intraperitoneal injection to destroy islet B cells. Male Sprague Dawley rats were administrated by intrathecal injection of P2X7 shRNA and p38 inhibitor, and we recorded abnormal mechanical and thermal pain and nociceptive hyperalgesia. One week later, the dorsal root ganglia from the L4-L6 segment of the spinal cord were harvested for subsequent experiments. We measured pro-inflammatory cytokines, examined the relationship between TRPV1 on neurons and P2X7 receptor on satellite glial cells by measuring protein and transcription levels of P2X7 receptor and TRPV1, and measured protein expression in the PKCε/P38 MAPK/NF-κB signaling pathway after intrathecal injection. P2X7 shRNA and p38 inhibitor relieved hyperalgesia in diabetic neuropathic pain rats and modulated inflammatory factors in vivo. P2X7 shRNA and P38 inhibitors significantly reduced TRPV1 expression by downregulating the PKCε/P38 MAPK/NF-κB signaling pathway and inflammatory factors in dorsal root ganglia. Intrathecal injection of P2X7 shRNA alleviates nociceptive reactions in rats with diabetic neuropathic pain involving TRPV1 via PKCε/P38 MAPK/NF-κB signaling pathway.

Iron accelerates Fusobacterium nucleatum-induced CCL8 expression in macrophages and is associated with colorectal cancer progression

Accumulating evidence suggests that high levels of Fusobacterium nucleatum in colorectal tumor tissues can be associated with poor prognosis in patients with colorectal cancer (CRC); however, data regarding distinct prognostic subgroups in F. nucleatum-positive CRC remain limited. Herein, we demonstrate that high-iron status was associated with a worse prognosis in patients with CRC with F. nucleatum. Patients with CRC presenting elevated serum transferrin saturation exhibited preferential iron deposition in macrophages in the tumor microenvironment. In addition, F. nucleatum induced CCL8 expression in macrophages via the TLR4/NF-κB signaling pathway, which was inhibited by iron deficiency. Mechanistically, iron attenuated the inhibitory phosphorylation of NF-κB p65 by activating serine/threonine phosphatases, augmenting tumor-promoting chemokine production in macrophages. Our observations indicate a key role for iron in modulating the NF-κB signaling pathway and suggest its prognostic potential as a determining factor for interpatient heterogeneity in F. nucleatum-positive CRC.

The positive regulatory loop of TCF4N/p65 promotes glioblastoma tumourigenesis and chemosensitivity

Background

NF‐κB signaling is widely linked to the pathogenesis and treatment resistance in cancers. Increasing attention has been paid to its anti‐oncogenic roles, due to its key functions in cellular senescence and the senescence‐associated secretory phenotype (SASP). Therefore, thoroughly understanding the function and regulation of NF‐κB in cancers is necessary prior to the application of NF‐κB inhibitors.

Methods

We established glioblastoma (GBM) cell lines expressing ectopic TCF4N, an isoform of the β‐catenin interacting transcription factor TCF7L2, and evaluated its functions in GBM tumorigenesis and chemotherapy in vitro and in vivo. In p65 knock‐out or phosphorylation mimic (S536D) cell lines, the dual role and correlation of TCF4N and NF‐κB signaling in promoting tumorigenesis and chemosensitivity was investigated by in vitro and in vivo functional experiments. RNA‐seq and computational analysis, immunoprecipitation and ubiquitination assay, minigene splicing assay and luciferase reporter assay were performed to identify the underlying mechanism of positive feedback regulation loop between TCF4N and the p65 subunit of NF‐κB. A eukaryotic cell‐penetrating peptide targeting TCF4N, 4N, was used to confirm the therapeutic significance.

Results

Our results indicated that p65 subunit phosphorylation at Ser 536 (S536) and nuclear accumulation was a promising prognostic marker for GBM, and endowed the dual functions of NF‐κB in promoting tumorigenesis and chemosensitivity. p65 S536 phosphorylation and nuclear stability in GBM was regulated by TCF4N. TCF4N bound p65, induced p65 phosphorylation and nuclear translocation, inhibited its ubiquitination/degradation, and subsequently promoted NF‐κB activity. p65 S536 phosphorylation was essential for TCF4N‐led senescence‐independent SASP, GBM tumorigenesis, tumor stem‐like cell differentiation and chemosensitivity. Activation of p65 was closely connected to alterative splicing of TCF4N, a likely positive feedback regulation loop between TCF4N and p65 in GBM. 4N increased chemosensitivity, highlighting a novel anti‐cancer strategy.

Conclusion

Our study defined key roles of TCF4N as a novel regulator of NF‐κB through mutual regulation with p65 and provided a new avenue for GBM inhibition.

Innate immunity and immunotherapy for hemorrhagic shock

Hemorrhagic shock (HS) is a shock result of hypovolemic injury, in which the innate immune response plays a central role in the pathophysiology ofthe severe complications and organ injury in surviving patients. During the development of HS, innate immunity acts as the first line of defense, mediating a rapid response to pathogens or danger signals through pattern recognition receptors. The early and exaggerated activation of innate immunity, which is widespread in patients with HS, results in systemic inflammation, cytokine storm, and excessive activation of complement factors and innate immune cells, comprised of type II innate lymphoid cells, CD4⁺ T cells, natural killer cells, eosinophils, basophils, macrophages, neutrophils, and dendritic cells. Recently, compelling evidence focusing on the innate immune regulation in preclinical and clinical studies promises new treatment avenues to reverse or minimize HS-induced tissue injury, organ dysfunction, and ultimately mortality. In this review, we first discuss the innate immune response involved in HS injury, and then systematically detail the cutting-edge therapeutic strategies in the past decade regarding the innate immune regulation in this field; these strategies include the use of mesenchymal stem cells, exosomes, genetic approaches, antibody therapy, small molecule inhibitors, natural medicine, mesenteric lymph drainage, vagus nerve stimulation, hormones, glycoproteins, and others. We also reviewed the available clinical studies on immune regulation for treating HS and assessed the potential of immune regulation concerning a translation from basic research to clinical practice. Combining therapeutic strategies with an improved understanding of how the innate immune system responds to HS could help to identify and develop targeted therapeutic modalities that mitigate severe organ dysfunction, improve patient outcomes, and reduce mortality due to HS injury.

Functional Crosstalk between PCSK9 Internalization and Pro-Inflammatory Activation in Human Macrophages: Role of Reactive Oxygen Species Release

Atherosclerosis is a cardiovascular disease caused mainly by dyslipidemia and is characterized by the formation of an atheroma plaque and chronic inflammation. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protease that induces the degradation of the LDL receptor (LDLR), which contributes to increased levels of LDL cholesterol and the progress of atherosclerosis. Given that macrophages are relevant components of the lipidic and inflammatory environment of atherosclerosis, we studied the effects of PCSK9 treatment on human macrophages. Our data show that human macrophages do not express PCSK9 but rapidly incorporate the circulating protein through the LDLR and also activate the pro-inflammatory TLR4 pathway. Both LDLR and TLR4 are internalized after incubation of macrophages with exogenous PCSK9. PCSK9 uptake increases the production of reactive oxygen species and reduces the expression of genes involved in lipid metabolism and cholesterol efflux, while enhancing the production of pro-inflammatory cytokines through a TLR4-dependent mechanism. Under these conditions, the viability of macrophages is compromised, leading to increased cell death. These results provide novel insights into the role of PCSK9 in the crosstalk of lipids and cholesterol metabolism through the LDLR and on the pro-inflammatory activation of macrophages through TLR4 signaling. These pathways are relevant in the outcome of atherosclerosis and highlight the relevance of PCSK9 as a therapeutic target for the treatment of cardiovascular diseases.

Upregulation of RCAN1.4 by HIF1α alleviates OGD-induced inflammatory response in astrocytes

OBJECTIVE

Ischemic stroke is a leading cause of human mortality and long-term disability worldwide. As one of the main forms of regulator of calcineurin 1 (RCAN1), the contribution of RCAN1.4 in diverse biological and pathological conditions has been implicated. But the role of RCAN1.4 in ischemic stroke progression remains elusive. This study is to explore the expression changes and roles of RCAN1.4 in ischemic stroke as well as the underlying mechanisms for these changes and effects of RCAN1.4 in ischemic stroke.

METHODS

Middle cerebral artery occlusion model in C57BL/6J mice and oxygen-glucose deprivation (OGD) model in primary astrocytes were performed to induce the cerebral ischemic stroke. The expression pattern of RCAN1.4 was assessed using real-time quantitative PCR and western blotting in vivo and in vitro. Mechanistically, the underlying mechanism for the elevation of RCAN1.4 in the upstream was investigated. Lentiviruses were administrated, and the effect of RCAN1.4 in postischemic inflammation was clearly clarified.

RESULTS

Here we uncovered that RCAN1.4 was dramatically increased in mouse ischemic brains and OGD-induced primary astrocytes. HIF1α, activated upon OGD, significantly upregulated RCAN1.4 gene expression through specifically binding to the RCAN1.4 promoter region and activating its promoter activity. The functional hypoxia-responsive element (HRE) was located between -254 and -245 bp in the RCAN1.4 promoter region. Moreover, elevated RCAN1.4 alleviated the release of pro-inflammatory cytokines TNFα, IL1β, IL6 and reduced expression of iNOS, COX2 in primary astrocytes upon OGD, whereas RCAN1.4 silencing has the opposite effect. Of note, RCAN1.4 overexpression inhibited OGD-induced NF-κB activation in primary astrocytes, leading to decreased degradation of IκBα and reduced nuclear translocation of NF-κB/p65.

INTERPRETATION

Our results reveal a novel mechanism underscoring the upregulation of RCAN1.4 by HIF1α and the protective effect of RCAN1.4 against postischemic inflammation, suggesting its significance as a promising therapeutic target for ischemic stroke treatment.

Protective effects of di-caffeoylquinic acids from Artemisia selengensis Turcz leaves against monosodium urate-induced inflammation via the modulation of NLRP3 inflammasome and Nrf2 signaling pathway in THP-1 macrophages

Artemisia selengensis Turcz (AST) as a common vegetable is rich in di-caffeoylquinic acids (di-CQAs) and has been reported to possess multiple health benefits. However, whether di-CQAs from AST leaf extracts (ASTE) could alleviate gout inflammation is still unknown. Herein, this study explored the inhibitory mechanism of ASTE on gout inflammation in THP-1 macrophages. Results suggested that ASTE suppressed the secretion and mRNA levels of inflammatory cytokines including interleukin-18, interleukin-1β, interleukin-6, and tumor necrosis factor-α. Pretreatment with ASTE inhibited lipopolysaccharide-induced of IκBα degradation, p65 phosphorylation and up-regulation of Nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome proteins. Moreover, ASTE inhibited monosodium urate-induced the up-regulation of active caspase-1 and interleukin-1β, promoted nuclear factor E2-related factor2 (Nrf2) to translocate into the nucleus, reducing the generation of MSU-induced reactive oxygen species. These results suggested that ASTE alleviated gout inflammation via inhibiting NLRP3 inflammasome activation and activating Nrf2 signaling pathway. PRACTICAL APPLICATIONS: Artemisia selengensis Turcz (AST) as a common vegetable in China belongs to genus Artemisia, which are rich in di-caffeoylquinic acids. This study aimed to investigate the effect of ASTE on alleviating gout inflammation and whether NLRP3 inflammasome and Nrf2 signaling pathways are involved in the protection of ASTE against gout inflammation. Our findings are significant for developing di-CQAs from AST by-products as an effective functional food for preventing gout.

ICAM-1-related noncoding RNA accelerates atherosclerosis by amplifying NF-κB signaling

Long noncoding RNAs (lncRNAs) are critical regulators of inflammation with great potential as new therapeutic targets. However, the role of lncRNAs in early atherosclerosis remains poorly characterized. This study aimed to identify the key lncRNA players in activated endothelial cells (ECs). The lncRNAs in response to pro-inflammatory factors in ECs were screened through RNA sequencing. ICAM-1-related non-coding RNA (ICR) was identified as the most potential candidate for early atherosclerosis. ICR is essential for intercellular adhesion molecule-1 (ICAM1) expression, EC adhesion and migration. In a high fat diet-induced atherosclerosis model in mice, ICR is upregulated in the development of atherosclerosis. After intravenous injection of adenovirus carrying shRNA for mouse ICR, the atherosclerotic plaque area was markedly reduced with the declined expression of ICR and ICAM1. Mechanistically, ICR stabilized the mRNA of ICAM1 in quiescent ECs; while under inflammatory stress, ICR upregulated ICAM1 in a nuclear factor kappa B (NF-κB) dependent manner. RNA-seq analysis showed pro-inflammatory targets of NF-κB were regulated by ICR. Furthermore, the chromatin immunoprecipitation assays showed that p65 binds to ICR promoter and facilitates its transcription. Interestingly, ICR, in turn, promotes p65 accumulation and activity, forming a positive feedback loop to amplify NF-κB signaling. Preventing the degradation of p65 using proteasome inhibitors rescued the expression of NF-κB targets suppressed by ICR. Taken together, ICR acts as an accelerator to amplify NF-κB signaling in activated ECs and suppressing ICR is a promising early intervention for atherosclerosis through ICR/p65 loop blockade.

Adipose-derived exosomes block muscular stem cell proliferation in aged mouse by delivering miRNA Let-7d-3p that targets transcription factor HMGA2

Sarcopenia is an aging-associated attenuation of muscular volume and strength and is the major cause of frailty and falls in elderly individuals. The number of individuals with sarcopenia is rapidly increasing worldwide; however, little is known about the underlying mechanisms of the disease. Sarcopenia often copresents with obesity, and some patients with sarcopenia exhibit accumulation of peri-organ or intra-organ adipose tissue as ectopic fat deposition, including atrophied skeletal muscle. In this study, we showed that transplantation of the perimuscular adipose tissue (PMAT) to the hindlimb thigh muscles of young mice decreased the number of integrin α7/CD29-double positive muscular stem/progenitor cells and that the reaction was mediated by PMAT-derived exosomes. We also found that the inhibition of cell proliferation was induced by Let-7d-3p miRNA that targets HMGA2, which is an important transcription factor for stem cell self-renewal, in muscular stem/progenitor cells and the composite molecular reaction in aged adipocytes. Reduction of Let-7 miRNA repressor Lin28 A/B and activation of nuclear factor-kappa B signaling can lead to the accumulation of Let-7d-3p in the exosomes of aged PMAT. These findings suggest a novel crosstalk between adipose tissue and skeletal muscle in the development of aging-associated muscular atrophy and indicate that adipose tissue–derived miRNAs may play a key role in sarcopenia.

Three phlorotannins from Sargassum carpophyllum are effective against the secretion of allergic mediators from antigen-stimulated rat basophilic leukemia cells

Sargassum carpophyllum (Sargassaceae) is a brown seaweed that contains phlorotannins, which are phloroglucinol polymers with reported anti-inflammatory activities. The phlorotannins 2-[2-(3,5-dihydroxyphenoxy)-3,5-dihydroxyphenoxy]-1,3,5-benzenetriol (1), 2,2'-[[2-(3,5-dihydroxyphenoxy)-5-hydroxy-1,3-phenylene]bis(oxy)]bis(1,3,5-benzenetriol) (2), and 2-[2-[4-[2-(3,5-dihydroxyphenoxy)-3,5-dihydroxyphenoxy]-3,5-dihydroxyphenoxy]-3,5-dihydroxyphenoxy]-1,3,5-benzenetriol (3) were isolated from S. carpophyllum. Here, we evaluated the anti-allergic activities of these compounds and comprehensively explored their effects on intracellular protein levels. Immunoglobulin E-sensitized rat basophilic leukemia cells pretreated with any of these three compounds exhibited reduced β-hexosaminidase, prostaglandin D2, and tumor necrosis factor-α secretion compared with dinitrophenyl-human serum albumin (DNP-HSA)-stimulated cells. Reduction of β-hexosaminidase release was dose-dependent but the half-maximal inhibitory concentrations of the compounds were similar (36-51 μM). Proteomics analysis revealed that the three compounds up-regulated 25 proteins and down-regulated 33 proteins compared with DNP-HSA stimulation alone, and slightly suppressed proteasome 5 expression linked to the regulation of IκB. These results demonstrate that these phlorotannins are potentially useful for preventing immediate hypersensitivity. S. carpophyllum may be a functional food.

Human MicroRNAs Attenuate the Expression of Immediate Early Proteins and HCMV Replication during Lytic and Latent Infection in Connection with Enhancement of Phosphorylated RelA/p65 (Serine 536) That Binds to MIEP

Attenuating the expression of immediate early (IE) proteins is essential for controlling the lytic replication of human cytomegalovirus (HCMV). The human microRNAs (hsa-miRs), miR-200b-3p and miR-200c-3p, have been identified to bind the 3′-untranslated region (3′-UTR) of the mRNA encoding IE proteins. However, whether hsa-miRs can reduce IE72 expression and HCMV viral load or exhibit a crosstalk with the host cellular signaling machinery, most importantly the NF-κB cascade, has not been evaluated. In this study, argonaute-crosslinking and immunoprecipitation-seq revealed that miR-200b-3p and miR-200c-3p bind the 3′-UTR of UL123, which is a gene that encodes IE72. The binding of these miRNAs to the 3′-UTR of UL123 was verified in transfected cells stably expressing GFP. We used miR-200b-3p/miR-200c-3p mimics to counteract the downregulation of these miRNA after acute HCMV infection. This resulted in reduced IE72/IE86 expression and HCMV VL during lytic infection. We determined that IE72/IE86 alone can inhibit the phosphorylation of RelA/p65 at the Ser⁵³⁶ residue and that p-Ser⁵³⁶ RelA/p65 binds to the major IE promoter/enhancer (MIEP). The upregulation of miR-200b-3p and miR-200c-3p resulted in the phosphorylation of RelA/p65 at Ser⁵³⁶ through the downregulation of IE, and the binding of the resultant p-Ser⁵³⁶ RelA/p65 to MIEP resulted in a decreased production of pro-inflammatory cytokines. Overall, miR-200b-3p and miR-200c-3p—together with p-Ser⁵³⁶ RelA/p65—can prevent lytic HCMV replication during acute and latent infection

ZCL-082, a boron-containing compound, induces apoptosis of non-Hodgkin's lymphoma via targeting p90 ribosomal S6 kinase 1/NF-κB signaling pathway

INTRODUCTION

Despite the rapid progress in the diagnosis and treatment, the prognosis of some types of non-Hodgkin's lymphoma (NHL), especially those with double-hit or double-expressor genotypes, remains poor. Novel targets and compounds are needed to improve the prognosis of NHL.

METHODS

We investigated the effect of ZCL-082, a novel boron-containing compound with anti-proliferating activity against ovarian cancer cells, on NHL cells and human peripheral blood mononuclear cells by CCK-8 assay, Annexin V/PI double staining assay, RH123/PI double staining, Western blot, and immunohistochemistry. NF-κB pathway activity was analyzed using luciferase reporter gene assay and RT-PCR. The location of p65 was detected by immunofluorescence and nuclear/cytoplasmic fractionation assay. Immunoprecipitation and chromatin immunoprecipitation assays were used to detect the binding between p65 and p300. CETSA and molecular docking assay were carried out to test the interaction between ZCL-082 and p90 ribosomal S6 kinase 1 (RSK1). Kinase reaction was conducted to examine the inhibition of RSK1 kinase activity by ZCL-082.

RESULTS

We found that ZCL-082 can induce the apoptosis of various NHL cell lines in vitro and in vivo. ZCL-082 significantly inhibits TNFα- or LPS-induced NF-κB activation without disturbing TNFα-induced IκBα degradation or the nuclear translocation and DNA-binding ability of p65. However, ZCL-082 markedly suppresses the phosphorylation of p65 on Ser536 and the interaction between p65 and p300. The overexpression of the phosphomimetic mutant of p65 at Ser536 partially abrogates ZCL-082-induced cell death. We further found that ZCL-082 directly binds to and inhibits the activity of RSK1. RSK1 can phosphorylate RelA/p65 on Ser536 and its overexpression is associated with the poor prognosis of lymphoma. The overexpression of RSK1 partially rescues ZCL-082-induced cell death. Molecular docking studies show that ZCL-082 fits well with the N-terminal kinase domain of RSK1. Furthermore, the combination of ZCL-082 and BCL-2 inhibitor ABT-199 has a synergistic apoptosis-inducing effect against double-hit lymphoma cell line OCI-Ly10.

DISCUSSION

We found that ZCL-082 is a highly promising anti-lymphoma compound that targets RSK1 and interferes with the RSK1/NF-κB signaling pathway. The combination of ZCL-082 with BCL-2 inhibitor may represent a novel strategy to improve the outcome of double-hit or double-expressor lymphoma.

Revealing the suppressive role of protein kinase C delta and p38 mitogen-activated protein kinase (MAPK)/NF-κB axis associates with lenvatinib-inhibited progression in hepatocellular carcinoma in vitro and in vivo

Nuclear factor-kappa B (NF-κB), an oncogenic transcription factor, modulates tumor formation and progression by inducing the expression of oncogenes involved in proliferation, survival, angiogenesis, and metastasis. Oral multikinase inhibitors, such as sorafenib, regorafenib, and lenvatinib have been used for the treatment of hepatocellular carcinoma (HCC). Both sorafenib and regorafenib were shown to abolish the NF-κB-mediated progression of HCC. However, the effect of lenvatinib on NF-κB-mediated progression of HCC is ambiguous. Therefore, the primary purpose of the present study was to evaluate the inhibitory effect of lenvatinib and its inhibitory mechanism on the NF-κB-mediated progression of HCC in vitro and in vivo. Here, we used two HCC cell lines to identify the cytotoxicity, apoptosis and metastasis effect of lenvatinib. We also applied a Hep3B-bearing animal model to investigate the therapeutic efficacy of lenvatinib on in vivo model. An NF-κB translocation assay, NF-κB reporter gene assay, a Western blotting assay and immunohistochemistry staining were used to investigate the underlying mechanism by which lenvatinib acts on HCC. In this study, we demonstrated that lenvatinib induced extrinsic/intrinsic apoptosis and suppressed the metastasis of HCC both in vitro and in vivo. Lenvatinib may also suppress NF-κB translocation and activation. We also found both protein kinase C delta (PKC-δ) and p38 mitogen-activated protein kinase (MAPK) inactivation participated in lenvatinib-reduced NF-κB signaling. In conclusion, this study reveals that the suppression of PKC-δ, and the p38 MAPK/NF-κB axis is associated with the lenvatinib-inhibited progression of HCC in vitro and in vivo.

Genomic and epigenomic adaptation in SP-R210 (Myo18A) isoform-deficient macrophages

Macrophages play an important role in maintaining tissue homeostasis, from regulating the inflammatory response to pathogens to resolving inflammation and aiding tissue repair. The surfactant protein A (SP-A) receptor SP-R210 (MYO18A) has been shown to affect basal and inflammatory macrophage states. Specifically, disruption of the longer splice isoform SP-R210_L/MYO18Aα renders macrophages hyper-inflammatory, although the mechanism by which this occurs is not well understood. We asked whether disruption of the L isoform led to the hyper-inflammatory state via alteration of global genomic responses. RNA sequencing analysis of L isoform-deficient macrophages (SP-R210_L(DN)) revealed basal and influenza-induced upregulation of genes associated with inflammatory pathways, such as TLR, RIG-I, NOD, and cytoplasmic DNA signaling, whereas knockout of both SP-R210 isoforms (L and S) only resulted in increased RIG-I and NOD signaling. Chromatin immunoprecipitation sequencing (ChIP-seq) analysis showed increased genome-wide deposition of the pioneer transcription factor PU.1 in SP-R210_L(DN) cells, with increased representation around genes relevant to inflammatory pathways. Additional ChIP-seq analysis of histone H3 methylation marks showed decreases in both repressive H3K9me3 and H3K27me3 marks with a commensurate increase in transcriptionally active (H3K4me3) histone marks in the L isoform deficient macrophages. Influenza A virus (IAV) infection, known to stimulate a wide array of anti-viral responses, caused a differential redistribution of PU.1 binding between proximal promoter and distal sites and decoupling from Toll-like receptor regulated gene promoters in SP-R210_L(DN) cells. These finding suggest that the inflammatory differences seen in SP-R210_L-deficient macrophages are a result of transcriptional differences that are mediated by epigenetic changes brought about by differential expression of the SP-R210 isoforms. This provides an avenue to explore how the signaling pathways downstream of the receptor and the ligands can modulate the macrophage inflammatory response.

Paeonol Ameliorates Abdominal Aortic Aneurysm Progression by the NF-κB Pathway

OBJECTIVE

Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease characterized by localized progressive dilatation. Currently, paeonol has been shown to possess anti-inflammatory and protective cardiovascular properties. Our study aimed to investigate the potential influences of paeonol on AAA progression.

METHODS

Experimental AAAs were created in C57BL/6J mice by intra-aortic infusion of porcine pancreatic elastase, and then intragastrically administered paeonol (20 mg/kg/day) for 14 days. The effects of paeonol on experimental AAA were measured by ultrasound imaging, histopathology, and western blot analyses.

RESULTS

Paeonol treatment limited the enlargement of the aneurysmal diameter and alleviated the depletion of elastic fibers and vascular smooth muscle cells (VSMCs). Furthermore, the infiltration of CD68+ macrophages and CD8+ lymphocytes was obviously attenuated after paeonol administration, along with mural neoangiogenesis. Western blot results showed that paeonol inhibited the expression of matrix metalloproteinase (MMP) and the NF-κB pathway activation.

CONCLUSIONS

Paeonol might prevent experimental AAA progression by inhibiting the NF-κB pathway, which suggests that it is a potential drug for AAA.

Monitoring the Levels of Cellular NF-κB Activation States

The NF-κB signaling system plays an important regulatory role in the control of many biological processes. The activities of NF-κB signaling networks and the expression of their target genes are frequently elevated in pathophysiological situations including inflammation, infection, and cancer. In these conditions, the outcome of NF-κB activity can vary according to (i) differential activation states, (ii) the pattern of genomic recruitment of the NF-κB subunits, and (iii) cellular heterogeneity. Additionally, the cytosolic NF-κB activation steps leading to the liberation of DNA-binding dimers need to be distinguished from the less understood nuclear pathways that are ultimately responsible for NF-κB target gene specificity. This raises the need to more precisely determine the NF-κB activation status not only for the purpose of basic research, but also in (future) clinical applications. Here we review a compendium of different methods that have been developed to assess the NF-κB activation status in vitro and in vivo. We also discuss recent advances that allow the assessment of several NF-κB features simultaneously at the single cell level.

Enriched Environment Attenuates Pyroptosis to Improve Functional Recovery After Cerebral Ischemia/Reperfusion Injury

Enriched environment (EE) is a complex containing social, cognitive, and motor stimuli. Exposure to EE can promote functional recovery after ischemia/reperfusion (I/R) injury. However, the underlying mechanisms remained unclear. Pyroptosis has recently been identified and demonstrated a significant role in ischemic stroke. The purpose of this study was to explore the effect of EE on neuronal pyroptosis after cerebral I/R injury. In the current study, middle cerebral artery occlusion/reperfusion (MCAO/R) was applied to establish the cerebral I/R injury model. Behavior tests including the modified Neurological Severity Scores (mNSS) and the Morris Water Maze (MWM) were performed. The infarct volume was evaluated by Nissl staining. To evaluate the levels of pyroptosis-related proteins, the levels of GSDMD-N and nod-like receptor protein 1/3 (NLRP1/3) inflammasome-related proteins were examined. The mRNA levels of IL-1β and IL-18 were detected by Quantitative Real-Time PCR (qPCR). The secretion levels of IL-1β and IL-18 were analyzed by ELISA. Also, the expression of p65 and p-p65 were detected. The results showed that EE treatment improved functional recovery, reduced infarct volume, attenuated neuronal pyroptosis after cerebral I/R injury. EE treatment also suppressed the activities of NLRP1/NLRP3 inflammasomes. These may be affected by inhabiting the NF-κB p65 signaling pathway. Our findings suggested that neuronal pyroptosis was probably the neuroprotective mechanism that EE treatment rescued neurological deficits after I/R injury.

Formononetin ameliorates IL‑13‑induced inflammation and mucus formation in human nasal epithelial cells by activating the SIRT1/Nrf2 signaling pathway

Formononetin has proven to be anti‑inflammatory and able to alleviate symptoms of certain allergic diseases. The present study aimed to determine and elucidate the potential effects of formononetin in allergic rhinitis. JME/CF15 cells were pretreated with formononetin at different doses, followed by stimulation with IL‑13. Cell Counting Kit‑8 assay was performed to determine the cytotoxicity of formononetin. The expression levels of inflammation‑related proteins, histamine, IgE, TNF‑α, IL‑1β, IL‑6, granulocyte‑macrophage colony‑stimulating factor and eotaxin in IL‑13‑stimulated JME/CF15 cells were detected using ELISAs. The expression levels of phosphorylated‑NF‑κB p65, NF‑κB p65 and cyclooxygenase‑2 (Cox‑2) were analyzed using western blotting. Reverse transcription‑quantitative PCR, western blotting and immunofluorescence were performed to measure the levels of mucin 5AC oligomeric mucus/gel‑forming. Expression levels of sirtuin 1 (SIRT1) and nuclear erythroid factor 2‑related factor 2 (Nrf2) proteins were also measured using western blotting. The results of the present study revealed that formononetin exerted no cytotoxic effect on the viability of JME/CF15 cells. Following stimulation of JME/CF15 cells with IL‑13, formononetin suppressed the upregulated expression levels of proinflammatory cytokines. IL‑13‑induced formation of mucus was also attenuated by formononetin treatment. Furthermore, it was found that the SIRT1/Nrf2 signaling pathway was activated in formononetin‑treated JME/CF15 cells, whereas treatment with the SIRT1 inhibitor, EX527, reversed the effects of formononetin on IL‑13‑induced inflammation and mucus formation in JME/CF15 cells. In conclusion, the findings of the current study indicated that formononetin may activate the SIRT1/Nrf2 signaling pathway, thereby inhibiting IL‑13‑induced inflammation and mucus formation in JME/CF15 cells. These results suggested that formononetin may represent a promising agent for the treatment of allergic rhinitis.

NF-κB: At the Borders of Autoimmunity and Inflammation

The transcription factor NF-κB regulates multiple aspects of innate and adaptive immune functions and serves as a pivotal mediator of inflammatory response. In the first part of this review, we discuss the NF-κB inducers, signaling pathways, and regulators involved in immune homeostasis as well as detail the importance of post-translational regulation by ubiquitination in NF-κB function. We also indicate the stages of central and peripheral tolerance where NF-κB plays a fundamental role. With respect to central tolerance, we detail how NF-κB regulates medullary thymic epithelial cell (mTEC) development, homeostasis, and function. Moreover, we elaborate on its role in the migration of double-positive (DP) thymocytes from the thymic cortex to the medulla. With respect to peripheral tolerance, we outline how NF-κB contributes to the inactivation and destruction of autoreactive T and B lymphocytes as well as the differentiation of CD4⁺-T cell subsets that are implicated in immune tolerance. In the latter half of the review, we describe the contribution of NF-κB to the pathogenesis of autoimmunity and autoinflammation. The recent discovery of mutations involving components of the pathway has both deepened our understanding of autoimmune disease and informed new therapeutic approaches to treat these illnesses.