Attenuated NF-κB Activation Research Articles

Propolis Extract Attenuates NF-κB Activation and Chronic Kidney Disease Progression in a Rat Model: Potential Surgical Adjuvant?

Background: Chronic kidney disease (CKD) is a global health concern often complicated by cardiovascular diseases like atherosclerosis. Both conditions share an inflammatory pathogenesis, with nuclear factor kappa B (NF-κB) playing a central role. Propolis, a natural bee product with anti-inflammatory properties, has shown potential in mitigating CKD progression. This study aimed to investigate the effects of propolis extract on NF-κB activation in a rat model of CKD, exploring its potential benefits as a surgical adjuvant. Methods: Male white rats (Rattus norvegicus) were divided into three groups: a control group, a CKD group, and a CKD+Propolis group receiving propolis extract (200 mg/kg body weight) daily for 20 days. CKD was induced using the unilateral ureteral obstruction (UUO) method. NF-κB levels were measured weekly using ELISA. Results: Propolis extract significantly reduced NF-κB levels in the CKD+Propolis group compared to the CKD group (p<0.05). This effect was consistently observed across all time points, indicating a sustained reduction in NF-κB activation with propolis treatment. Conclusion: Propolis extract effectively attenuates NF-κB activation in a rat model of CKD, suggesting its potential as an adjunctive therapy for CKD management, particularly in the context of surgical interventions. Further research is needed to elucidate the underlying mechanisms and evaluate its efficacy in human subjects.

Importin α4 deficiency induces psychiatric disorder-related behavioral deficits and neuroinflammation in mice

Importin α4, which is encoded by the Kpna4 gene, is a well-characterized nuclear-cytoplasmic transport factor known to mediate transport of transcription factors including NF-κB. Here, we report that Kpna4 knock-out (KO) mice exhibit psychiatric disorder-related behavioral abnormalities such as anxiety-related behaviors, decreased social interaction, and sensorimotor gating deficits. Contrary to a previous study predicting attenuated NF-κB activity as a result of Kpna4 deficiency, we observed a significant increase in expression levels of NF-κB genes and proinflammatory cytokines such as TNFα, Il-1β or Il-6 in the prefrontal cortex or basolateral amygdala of the KO mice. Moreover, examination of inflammatory responses in primary cells revealed that Kpna4 deficient cells have an increased inflammatory response, which was rescued by addition of not only full length, but also a nuclear transport-deficient truncation mutant of importin α4, suggesting contribution of its non-transport functions. Furthermore, RNAseq of sorted adult microglia and astrocytes and subsequent transcription factor analysis suggested increases in polycomb repressor complex 2 (PRC2) activity in Kpna4 KO cells. Taken together, importin α4 deficiency induces psychiatric disorder-related behavioral deficits in mice, along with an increased inflammatory response and possible alteration of PRC2 activity in glial cells.

Nerve growth factor receptor limits inflammation to promote remodeling and repair of osteoarthritic joints

Osteoarthritis (OA) is a painful, incurable disease affecting over 500 million people. Recent clinical trials of the nerve growth factor (NGF) inhibitors in OA patients have suggested adverse effects of NGF inhibition on joint structure. Here we report that nerve growth factor receptor (NGFR) is upregulated in skeletal cells during OA and plays an essential role in the remodeling and repair of osteoarthritic joints. Specifically, NGFR is expressed in osteochondral cells but not in skeletal progenitor cells and induced by TNFα to attenuate NF-κB activation, maintaining proper BMP-SMAD1 signaling and suppressing RANKL expression in mice. NGFR deficiency hyper-activates NF-κB in murine osteoarthritic joints, which impairs bone formation and enhances bone resorption as exemplified by a reduction in subchondral bone and osteophytes. In human OA cartilage, NGFR is also negatively associated with NF-κB activation. Together, this study suggests a role of NGFR in limiting inflammation for repair of diseased skeletal tissues.

BRISC is required for optimal activation of NF-κB in Kupffer cells induced by LPS and contributes to acute liver injury

BRISC (BRCC3 isopeptidase complex) is a deubiquitinating enzyme that has been linked with inflammatory processes, but its role in liver diseases and the underlying mechanism are unknown. Here, we investigated the pathophysiological role of BRISC in acute liver failure using a mice model induced by D-galactosamine (D-GalN) plus lipopolysaccharide (LPS). We found that the expression of BRISC components was dramatically increased in kupffer cells (KCs) upon LPS treatment in vitro or by the injection of LPS in D-GalN-sensitized mice. D-GalN plus LPS-induced liver damage and mortality in global BRISC-null mice were markedly attenuated, which was accompanied by impaired hepatocyte death and hepatic inflammation response. Constantly, treatment with thiolutin, a potent BRISC inhibitor, remarkably alleviated D-GalN/LPS-induced liver injury in mice. By using bone marrow-reconstituted chimeric mice and cell-specific BRISC-deficient mice, we demonstrated that KCs are the key effector cells responsible for protection against D-GalN/LPS-induced liver injury in BRISC-deficient mice. Mechanistically, we found that hepatic and circulating levels of TNF-α, IL-6, MCP-1, and IL-1β, as well as TNF-α- and MCP-1-producing KCs, in BRISC-deleted mice were dramatically decreased as early as 1 h after D-GalN/LPS challenge, which occurred prior to the elevation of the liver injury markers. Moreover, LPS-induced proinflammatory cytokines production in KCs was significantly diminished by BRISC deficiency in vitro, which was accompanied by potently attenuated NF-κB activation. Restoration of NF-κB activation by two small molecular activators of NF-κB p65 effectively reversed the suppression of cytokines production in ABRO1-deficient KCs by LPS. In conclusion, BRISC is required for optimal activation of NF-κB-mediated proinflammatory cytokines production in LPS-treated KCs and contributes to acute liver injury. This study opens the possibility to develop new strategies for the inhibition of KCs-driven inflammation in liver diseases.

Targeting Rev-Erbα to protect against ischemia-reperfusion-induced acute lung injury in rats

BackgroundThe dysregulation of local circadian clock has been implicated in the pathogenesis of a broad spectrum of diseases. However, the pathophysiological role of intrinsic circadian clocks Rev-Erbα in ischemia-reperfusion (IR)-induced acute lung injury (ALI) remains unclear.MethodsThe IR-ALI model was established by subjecting isolated perfused rat lungs to 40 min of ischemia followed by 60 min of reperfusion. Rats were randomly assigned to one of six groups: control, control + SR9009 (Rev-Erbα agonist, 50 mg/kg), IR, and IR + SR9009 at one of three dosages (12.5, 25, 50 mg/kg). Bronchoalveolar lavage fluids (BALF) and lung tissues were obtained and analyzed. In vitro experiments utilized mouse lung epithelial cells (MLE-12) exposed to hypoxia-reoxygenation (HR) and pretreated with SR9009 (10 µM/L) and Rev-Erbα siRNA.ResultsSR9009 exhibited a dose-dependent reduction in lung edema in IR-ALI. It significantly inhibited the production of TNF-α, IL-6, and CINC-1 in BALF. Moreover, SR9009 treatment restored suppressed IκB-α levels and reduced nuclear NF-κB p65 levels in lung tissues. In addition, a SR9009 mitigated IR-induced apoptosis and mitogen-activated protein kinase (MAPK) activation in injured lung tissue. Finally, treatment with Rev-Erbα antagonist SR8278 abolished the protective action of SR9009. In vitro analyses showed that SR9009 attenuated NF-κB activation and KC/CXCL-1 levels in MLE-12 cells exposed to HR, and these effects were significantly abrogated by Rev-Erbα siRNA.ConclusionsThe findings suggest that SR9009 exerts protective effects against IR-ALI in a Rev-Erbα-dependent manner. SR9009 may provide a novel adjuvant therapeutic approach for IR-ALI.

MitoQ combats tumor cell progression in Ehrlich ascites carcinoma mice: A crosstalk between mitochondrial oxidative status, mitophagy, and NF-κB signaling

Despite the clinical advances in cancer treatment, the high mortality rate is still a great challenge, requiring much effort to find new and efficient cancer therapies. AimsThe present evidence investigated the potential antiproliferative impact of the mitochondrial-targeted antioxidant, Mitoquinol (MitoQ), on a mouse model of Ehrlich ascites carcinoma (EAC). Main methodsMice-bearing tumors were administered two doses of MitoQ (0.3 mg & 0.5 mg/kg; i.p daily) or doxorubicin (2 mg/kg; i.p daily) for 20 days. Key findingsEAC mice revealed exacerbated mitochondrial reactive oxygen species (mtROS) and impaired mitochondrial membrane potential (△Ψm). Dysfunctional mitophagy was observed in EAC mice, along with boosting aerobic glycolysis. In addition, tumor cells exhibited higher proliferation rates, thereby stimulating cell cycle, invasion, and angiogenesis biomarkers together with suppressing proapoptotic proteins, events that might be correlated with activation of NF-κB signaling. The administration of MitoQ combated tumor cell survival and dissemination in EAC mice as evidenced by reducing tumor volumes and weights and increasing the number of necrotic areas in histopathological assessment. MitoQ also repressed tumor cell cycle, invasion, and angiogenesis via preventing cyclin D1 mRNA, MMP-1, and CD34 levels as well as VEGF protein expression. These observations were associated with the abrogation of mtROS overproduction and enhancement of the mitophagy proteins, PINK1/Parkin levels, followed by inhibition of NADH dehydrogenase. Notably, NF-κB signaling was modulated. SignificanceThis study suggests that MitoQ combated tumor cell survival and progression in EAC mice by maintaining mtROS and restoring mitophagy, thereby attenuation of NF-κB activation.

Effect of Hesperidin on Barrier Function and Reactive Oxygen Species Production in an Oral Epithelial Cell Model, and on Secretion of Macrophage-Derived Inflammatory Mediators during Porphyromonas gingivalis Infection.

Porphyromonas gingivalis is a periodontopathogenic bacterium that can adhere to and colonize periodontal tissues, leading to an inflammatory process, and, consequently, tissue destruction. New therapies using flavonoids, such as hesperidin, are being studied, and their promising properties have been highlighted. The aim of this study was to evaluate the effect of hesperidin on the epithelial barrier function, reactive oxygen species (ROS) production, and on the inflammatory response caused by P. gingivalis in in vitro models. The integrity of the epithelial tight junctions challenged by P. gingivalis was determined by monitoring the transepithelial electrical resistance (TER). P. gingivalis adherence to a gingival keratinocyte monolayer and a basement membrane model were evaluated by a fluorescence assay. A fluorometric assay was used to determine the ROS production in gingival keratinocytes. The level of pro-inflammatory cytokines and matrix metalloproteinases (MMPs) secretion was evaluated by ELISA; to assess NF-κB activation, the U937-3xjB-LUC monocyte cell line transfected with a luciferase reporter gene was used. Hesperidin protected against gingival epithelial barrier dysfunction caused by P. gingivalis and reduced the adherence of P. gingivalis to the basement membrane model. Hesperidin dose-dependently inhibited P. gingivalis-mediated ROS production by oral epithelial cells as well as the secretion of IL-1β, TNF-α, IL-8, MMP-2, and MMP-9 by macrophages challenged with P. gingivalis. Additionally, it was able to attenuate NF-κB activation in macrophages stimulated with P. gingivalis. These findings suggest that hesperidin has a protective effect on the epithelial barrier function, in addition to reducing ROS production and attenuating the inflammatory response associated with periodontal disease.

MiR-9 targeting RUNX1 improves LPS-induced alveolar hypercoagulation and fibrinolysis inhibition through NF-κB inactivation in ARDS

BackgroundAcute respiratory distress syndrome (ARDS) is a clinical and pathophysiological complex syndrome with high mortality. Alveolar hypercoagulation and fibrinolytic inhibition constitute the core part of the pathophysiology of ARDS. miR-9 (microRNA-9a-5p) plays an important role in the pathogenesis of ARDS, but whether it regulates alveolar pro-coagulation and fibrinolysis inhibition in ARDS remains to be elucidated. We aimed to determine the contributing role of miR-9 on alveolar hypercoagulation and fibrinolysis inhibition in ARDS. MethodsIn the ARDS animal model, we first observed the miR-9 and runt-related transcription factor 1 (RUNX1) expression in lung tissue, the effects of miR-9 on alveolar hypercoagulation and fibrinolytic inhibition in ARDS rats, and the efficacy of miR-9 on acute lung injury. In the cell, alveolar epithelial cells type II (AECII) were treated with LPS, and the levels of miR-9 and RUNX1 were detected. Then we observed the effects of miR-9 on procoagulant and fibrinolysis inhibitor factors in cells. Finally, we explored whether the efficacies of miR-9 were associated with RUNX1; we also preliminarily examined the miR-9 and RUNX1 levels in plasma in patients with ARDS. ResultsIn ARDS rats, miR-9 expression decreased, but RUNX1 expression increased in the pulmonary tissue of ARDS rats. miR-9 displayed to attenuate lung injury and pulmonary wet/dry ratio. Study results in vivo demonstrated that miR-9 ameliorated alveolar hypercoagulation and fibrinolysis inhibition and attenuated the collagen III expressions in tissue. miR-9 also inhibited NF-κB signaling pathway activation in ARDS. In LPS-induced AECII, the expression changes of both miR-9 and RUNX1 were similar to those in pulmonary tissue in the animal ARDS model. miR-9 effectively inhabited tissue factor (TF), plasma activator inhibitor (PAI-1) expressions, and NF-κB activation in LPS-treated ACEII cells. Besides, miR-9 directly targeted RUNX1, inhibiting TF and PAI-1 expression and attenuating NF-κB activation in LPS-treated AECII cells. Clinically, we preliminarily found that the expression of miR-9 was significantly reduced in ARDS patients compared to non-ARDS patients. ConclusionOur experimental data indicate that by directly targeting RUNX1, miR-9 improves alveolar hypercoagulation and fibrinolysis inhibition via suppressing NF-κB pathway activation in LPS-induced rat ARDS, implying that miR-9/RUNX1 is expected to be a new therapeutic target for ARDS treatment.

Abstract PR02: RSK1 targeting impedes oncogenic driver and inflammatory cytokine signaling to attenuate myeloid neoplasms

Abstract Myeloproliferative neoplasms (MPNs), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML) exist among a spectrum of myeloid malignancies, governed by critical genetic dependencies, and propagated by a ripe pro-inflammatory niche. We previously identified elevated RPS6KA1 (RSK1) expression in myeloid malignancies associated with poor overall survival. Here, we demonstrate that RSK1 plays a fundamental role in mediating inflammation and serves as a central signaling node driving leukemogenesis. We further evaluate a novel therapeutic regimen utilizing a first-in-class RSK1 inhibitor, PMD-026, currently evaluated in Phase 1/1b clinical trials for breast cancer, for use in myeloid malignancies. Plasma analysis of 144 MPN patients and RNA-seq of CD14+ monocytes from 54 MPN patients revealed enrichment of inflammatory cytokines and hyperactive NFκB signaling. RSK1 inhibition by shRNA or PMD-026 in THP-1 monocytic AML cells potently suppressed this NFκB node, decreased TNF and NFKB1 mRNA, and reduced luminescence in cells expressing a NFκB-luciferase reporter. Immunoblotting and cytokine mass cytometry revealed suppression of RelA/p65 phosphorylation with reduction of TNF, IL-6, IL-8, CCL3, and CCL4 in MPN and CMML CD14+ monocytes. We also observed that RSK1 inhibition attenuated NFκB activation by TNF, LPS, and Pam3CSK4, while also suppressing monocyte differentiation to M1 macrophages. In the MPL W515L myelofibrosis (MF) model, mice treated with PMD-026 had significant reduction in TNF, IL-6, IL-1b, CCL3, and CCL5 by multiplex cytokine profiling and diminished disease burden (reduction of leukocytosis, splenomegaly, and bone marrow fibrosis). Finally, amelioration of disease was observed across MF and sAML patient-derived xenograft (PDX) models with PMD-026 treatment. We extended our findings to FLT3-ITD de novo AML models, in which RSK1 inhibition led to lethality in FLT3-ITD cells and PMD-026 potently suppressed leukemic engraftment in a MV4-11 mouse xenograft. Both genetic and pharmacological inhibition of RSK1 reduced FLT3 phosphorylation and revealed a novel, bi-directional regulatory network. Moreover, we found that RSK1 perturbation also attenuated FLT3 expression and altered protein stability, which was not observed with FLT3 inhibitor quizartinib. Mechanistically, RSK1 modulated FLT3 dynamics through deubiquitinase USP1, which was downregulated upon RSK1 perturbation. USP1 perturbation led to cell death and phenocopied FLT3 suppression observed with RSK1 inhibition. We further identified elevated USP1 expression associated with worse survival outcomes across the TCGA LAML, BeatAML, and Leucegene cohorts, thus indicating the potential of USP1 as a novel biomarker. We uncover a role for targeting RSK1 as a two-pronged approach in reducing disease burden across myeloid malignancies via: 1) suppressing driver signaling, and 2) dampening the pro-inflammatory milieu. These findings highlight a critical dependency along the RSK1-USP1-FLT3 axis that is potentially exploitable with RSK1 inhibitors such as PMD-026. Citation Format: Tim Kong, Angelo Laranjeira, Stephen Oh. RSK1 targeting impedes oncogenic driver and inflammatory cytokine signaling to attenuate myeloid neoplasms [abstract]. In: Proceedings of the AACR Special Conference: Acute Myeloid Leukemia and Myelodysplastic Syndrome; 2023 Jan 23-25; Austin, TX. Philadelphia (PA): AACR; Blood Cancer Discov 2023;4(3_Suppl):Abstract nr PR02.

Citral protects against LPS-induced endometritis by inhibiting ferroptosis through activating Nrf2 signaling pathway.

Endometritis is the inflammatory condition of the uterus. Citral, a component of lemongrass oil, is known to exhibit anti-inflammatory activity. The effects of citral on LPS-induced endometritis were tested and the mechanisms were investigated. LPS-induced endometritis mice model was established and the effects of citral were detected using this model. Inflammatory cytokines were tested by ELISA. Ferroptosis was assessed by detecting GSH, ATP, MDA, and Fe2+ levels. Signaling pathway was tested by western blot analysis. Citral prevented LPS-induced endometritis through attenuating uterine pathological changes and inflammatory cytokine release. Meanwhile, citral prevents LPS-induced ferroptosis through attenuating MDA and Fe2+ levels, as well as increasing ATP and GSH levels. Furthermore, citral up-regulated Nrf2 and HO-1 expression and attenuated NF-κB activation. In addition, in Nrf2 knockdown mice, the inhibitory roles of citral on ferroptosis and endometritis were largely reversed. Taken together, citral inhibited LPS-induced endometritisthrough preventing ferroptosis, which were regulated by Nrf2 signaling pathway.

Attenuation of Lipopolysaccharide-Induced Inflammatory Responses through Inhibition of the NF-κB Pathway and the Increased NRF2 Level by a Flavonol-Enriched n-Butanol Fraction from Uvaria alba.

Pathologic hyperreactive inflammatory responses occur when there is excessive activation of a proinflammatory NF-κB pathway and a reduced cytoprotective NRF2 cascade. The noncytotoxic, highly selective COX-2 inhibitory flavonol-enriched butanol fraction (UaB) from Uvaria alba (U. alba) was investigated for its inflammatory modulating potential by targeting NF-κB activation and NRF2 activity. Enzyme-linked immunosorbent assay was initially performed to measure levels of proinflammatory mediators [nitric oxide (NO), prostaglandin E2, and reactive oxygen species (ROS)] and cytokines [tumor necrosis factor-alpha (TNF-α), IL-1β, and IL-6], followed by reverse transcription-polymerase chain reaction and western blotting to determine mRNA and protein expression, respectively. Using immunofluorescence staining combined with western blot analysis, the activation of NF-κB was further investigated. NRF2 activity was also measured using a luciferase reporter assay. UaB abrogated protein and mRNA expressions of inducible nitric oxide synthase (iNOS), COX-2, TNF-α, IL-1β, and IL-6 in RAW 264.7 macrophages, thereby suppressing the production of proinflammatory mediators and cytokines. This was further validated when a concentration-dependent decrease in NO and ROS production was observed in zebrafish (Danio rerio) larvae. UaB also increased NRF2 activity in HaCaT/ARE cell line and attenuated NF-κB activation by inhibiting the nuclear translocation of transcription factor p65 in RAW 264.7 macrophages. Nontargeted LC-MS analysis of UaB revealed the presence of the flavonols quercitrin (1), quercetin (2), rutin (3), kaempferol (4), and kaempferol 3-O-rutinoside (5). Molecular docking indicates that major flavonol aglycones have high affinity toward COX-2 NSAID-binding sites, TNF-α, and TNF-α converting enzyme, while the glycosylated flavonoids showed strong binding toward iNOS and IKK-all possessing dynamic stability when performing molecular dynamics simulations at 140 ns. This is the first report to have elucidated the mechanistic anti-inflammatory potential of the Philippine endemic plant U. alba.

Protective Effects of the Chalcone-Based Derivative AN07 on Inflammation-Associated Myotube Atrophy Induced by Lipopolysaccharide.

Inflammation is a major cause of skeletal muscle atrophy in various diseases. 2-Hydroxy-4'-methoxychalcone (AN07) is a chalcone-based peroxisome-proliferator-activated receptor gamma (PPARγ) agonist with various effects, such as antiatherosclerosis, anti-inflammation, antioxidative stress, and neuroprotection. In this study, we examined the effects of AN07 on protein homeostasis pathway and mitochondrial function in inflammation-associated myotube atrophy induced by lipopolysaccharides (LPS). We found that AN07 significantly attenuated NF-κB activation, inflammatory factors (TNF-α, IL-1β, COX-2, and PGE2), Nox4 expression, and reactive oxygen species levels in LPS-treated C2C12 myotubes. Moreover, AN07 increased SOD2 expression and improved mitochondrial function, including mitochondrial membrane potential and mitochondrial oxygen consumption rate. We also demonstrated that AN07 attenuated LPS-induced reduction of myotube diameter, MyHC expression, and IGF-1/IGF-1R/p-Akt-mediated protein synthesis signaling. Additionally, AN07 downregulated LPS-induced autophagy-lysosomal protein degradation molecules (LC3-II/LC3-I and degraded p62) and ubiquitin-proteasome protein degradation molecules (n-FoxO1a/MuRF1/atrogin-1). However, the regulatory effects of AN07 on protein synthesis and degradation signaling were inhibited by the IGF-1R inhibitor AG1024 and the PI3K inhibitor wortmannin. In addition, the PPARγ antagonist GW9662 attenuated the effects of AN07 against LPS-induced inflammation, oxidation, and protein catabolism. In conclusion, our findings suggest that AN07 possesses protective effects on inflammation-induced myotube atrophy and mitochondrial dysfunction.

Punicalagin Attenuates LPS-Induced Inflammation and ROS Production in Microglia by Inhibiting the MAPK/NF-κB Signaling Pathway and NLRP3 Inflammasome Activation.

PurposeNeurodegenerative diseases are associated with neuroinflammation along with activation of microglia and oxidative stress, but currently lack effective treatments. Punicalagin is a natural bio-sourced product that exhibits anti-inflammatory effects on several chronic diseases; however, the anti-inflammatory and anti-oxidative effects on microglia have not been well examined. This study aimed to investigate the effects of punicalagin on LPS-induced inflammatory responses, NLRP3 inflammasome activation, and the production of ROS using murine microglia BV2 cells.MethodsBV2 cells were pre-treated with punicalagin following LPS treatment to induce inflammation. The secretion of NO and PGE2 was analyzed by Griess reagent and ELISA respectively, while the expressions of iNOS, COX-2, STAT3, ERK, JNK, and p38 were analyzed using Western blotting, the production of IL-6 was measured by ELISA, and the activity of NF-κB was detected using promoter reporter assay. To examine whether punicalagin affects NLRP3 inflammasome activation, BV2 cells were stimulated with LPS and then treated with ATP or nigericin. The secretion of IL-1β was measured by ELISA. The expressions of NLRP3 inflammasome-related proteins and phospho IκBα/IκBα were analyzed using Western blotting. The production of intracellular and mitochondrial ROS was analyzed by flow cytometry.ResultsOur results showed that punicalagin attenuated inflammation with reduction of pro-inflammatory mediators and cytokines including iNOS, COX-2, IL-1β, and reduction of IL-6 led to inhibition of STAT3 phosphorylation by LPS-induced BV2 cells. Punicalagin also suppressed the ERK, JNK, and p38 phosphorylation, attenuated NF-κB activity, inhibited the activation of the NLRP3 inflammasome, and reduced the production of intracellular and mitochondrial ROS by LPS-induced BV2 cells.ConclusionOur results demonstrated that punicalagin attenuated LPS-induced inflammation through suppressing the expression of iNOS and COX-2, inhibited the activation of MAPK/NF-κB signaling pathway and NLRP3 inflammasome, and reduced the production of ROS in microglia, suggesting that punicalagin might have the potential in treating neurodegenerative diseases.

Acetate, a gut bacterial product, ameliorates ischemia-reperfusion induced acute lung injury in rats

Recent data suggest that short-chain fatty acids (SCFAs), the major fermentation product from gut microbial degradation of dietary fiber, have protective effects against renal ischemia–reperfusion (IR) injury, colitis, and allergic asthma. However, the effect of SCFAs on acute lung injury (ALI) caused by IR is still unclear. In this study, we examine whether SCFAs have protective effects against IR-induced ALI and explore possible protective mechanisms. IR-induced ALI was established by 40 min ischemia followed by 60 min reperfusion in isolated perfused rat lungs. Rats were randomly assigned to one of six groups: control, control + acetate (400 mg/kg), IR, and IR + acetate at one of three dosages (100, 200, 400 mg/kg). Bronchoalveolar lavage fluids (BALF) and lung tissues were obtained and analyzed at the end of the experiment. In vitro, mouse lung epithelial cells (MLE-12) subjected to hypoxia-reoxygenation (HR) were pretreated with acetate (25 mmol/L) and GPR41 or GPR43 siRNA. Acetate decreased lung weight gain, lung weight/body weight ratios, wet/dry weight ratios, pulmonary artery pressure, and protein concentration of the BALF in a dose-dependent manner for IR-induced ALI. Acetate also significantly inhibited the production of TNF-α, IL-6 and CINC-1 in the BALF. Moreover, acetate treatment restored suppressed IκB-α levels and reduced nuclear NF-κB p65 levels in lung tissues. In addition, acetate mitigated IR-induced apoptosis and tight junction disruption in injured lung tissue. In vitro analyses showed that acetate attenuated NF-κB activation and KC/CXCL-1 levels in MLE-12 cells exposed to HR. The protective effects of acetate in vitro were significantly abrogated by GPR41 or GPR43 siRNA. Acetate ameliorates IR-induced acute lung inflammation and its protective mechanism appears to be via the GPR41/43 signaling pathway. Based on our findings, acetate may provide a novel adjuvant therapeutic approach for IR-induced lung injury.

Functionalized core-shell nanogel scavenger for immune modulation therapy in sepsis.

Sepsis is a complex, life-threatening hyperinflammatory syndrome associated with organ failure and high mortality due to lack of effective treatment options. Here we report a core-shell hydrogel nanoparticle with the core functionalized with telodendrimer (TD) nanotrap (NT) to control hyperinflammation in sepsis. The combination of multi-valent charged and hydrophobic moieties in TD enables effective binding with biomolecules in NT. The higher crosslinking in the shell structure of nanogel excludes the abundant large serum proteins and allows for size-selectivity in scavenging the medium-sized septic molecules (10-30 kDa), e.g., lipopolysaccharides (LPS, a potent endotoxin in sepsis), thus reducing cytokine production. At the same time, the core-shell TD NT nanogel captures the over-flowing proinflammatory cytokines effectively both in vitro and in vivo from biological fluids to further control hyperinflammation. Intraperitoneal injection of core-shell TD NT nanogel effectively attenuates NF-κB activation and cytokine production in LPS-induced septic mouse models. These results indicate the potential applications of the injectable TD NT core-shell nanogel to attenuate local or systemic inflammation.

ABIN1 is a signal-induced autophagy receptor that attenuates NF-κB activation by recognizing linear ubiquitin chains.

Linear ubiquitin chains play pivotal roles in immune signaling by augmenting NF-κB activation and suppressing programmed cell death induced by various stimuli. A20-binding inhibitor of NF-κB 1 (ABIN1) binds to linear ubiquitin chains and attenuates NF-κB activation and cell death induction. Although interactions with linear ubiquitin chains are thought to play a role in ABIN1-mediated suppression of NF-κB and cell death, the underlying molecular mechanisms remain unclear. Here, we show that upon stimulation by Toll-like receptor (TLR) ligands, ABIN1 is phosphorylated on Ser 83 and functions as a selective autophagy receptor. ABIN1 recognizes components of the MyD88 signaling complex via interaction with linear ubiquitin chains conjugated to components of the complex in TLR signaling, which leads to autophagic degradation of signaling proteins and attenuated NF-κB signaling. Our current findings indicate that phosphorylation and linear ubiquitination also play a role in downregulation of signaling via selective induction of autophagy.

Purple Corn Silk Extract Attenuates UVB-Induced Inflammation in Human Keratinocyte Cells

UVB is a causative factor for severe skin damage, such as cell aging, death, and inflammation. UVB easily permeates into the epidermis layer of human skin, which is mainly composed of keratinocyte cells. In previous results, we found that purple corn silk (PCS) extract showed the potential to inhibit keratinocyte damages of UVB-treated cells. Thus, in this study, we aimed to evaluate the preventive effects of PCS extract against the inflammation of UVB-induced keratinocyte cells using the HaCaT cell line. HaCaT cells were treated with PCS extract at various concentrations for 1 h, then exposed to 25 mJ/cm2 UVB before subsequent experiments. Fragmented DNA was observed using flow cytometry. The inflammatory response was investigated through NF-κB activity by immunofluorescence staining and related protein expression by Western blotting. The results demonstrated that PCS extract decreased the sub-G1 DNA content. Interestingly, PCS extract attenuated NF-κB activity via suppressed NF-κB nuclear translocation and protein expression. Moreover, PCS extract remarkably decreased c-Jun phosphorylation and decreased proinflammatory cytokines, along with iNOS and COX-2 levels in UVB-treated cells compared to the UVB-control group. This finding exhibited that PCS extract minimized inflammation in keratinocyte cells induced by UVB radiation.

LL-37 and Double-Stranded RNA Synergistically Upregulate Bronchial Epithelial TLR3 Involving Enhanced Import of Double-Stranded RNA and Downstream TLR3 Signaling.

The human host defense peptide LL-37 influences double-stranded RNA signaling, but this process is not well understood. Here, we investigate synergistic actions of LL-37 and synthetic double-stranded RNA (poly I:C) on toll-like receptor 3 (TLR3) expression and signaling, and examine underlying mechanisms. In bronchial epithelial BEAS-2B cells, LL-37 potentiated poly I:C-induced TLR3 mRNA and protein expression demonstrated by qPCR and Western blot, respectively. Interestingly, these effects were associated with increased uptake of rhodamine-tagged poly I:C visualized by immunocytochemistry. The LL-37/poly I:C-induced upregulation of TLR3 mRNA expression was prevented by the endosomal acidification inhibitor chloroquine, indicating involvement of downstream TLR3 signaling. The glucocorticoid dexamethasone reduced LL-37/poly I:C-induced TLR3 expression on both mRNA and protein levels, and this effect was associated with increased IκBα protein expression, suggesting that dexamethasone acts via attenuation of NF-κB activity. We conclude that LL-37 potentiates poly I:C-induced upregulation of TLR3 through a mechanism that may involve enhanced import of poly I:C and that LL-37/poly I:C-induced TLR3 expression is associated with downstream TLR3 signaling and sensitive to inhibition of NF-κB activity.

Neuromodulation of neurological disorders in a demyelination model: effect of a potassium channel inhibitor from Androctonus scorpion venom

Scorpion’s toxins have attracted attention as a treatment for diverse neurological diseases related to myelin loss. This study aimed to investigate the effect of kaliotoxin2 (KTX2), a potassium-channel blocker from Androctonus australis hector venom on cuprizone model of demyelination. Results showed that KTX2 modulates the behavioral functions, the demyelination, and reduces the recruitment of microglia, astrocytes, and granulocyte in the brain. KTX2 modulates the inflammatory response by increasing the IL-10 release, attenuating NFκB activation, and decreasing the oxidative stress markers and IL-6 levels. Results highlight the modulating effects of KTX2 on cuprizone model and confirm its therapeutic potential in demyelination diseases. Highlights Kaliotoxin2 (KTX2) prevents the excessive reduction in body weight gain and modulate motor coordination disorder induced by cuprizone. KTX2 from Aah venom protect myelin from the destructive effects of cuprizone. KTX2 inoculation to the CNS reduce microglia, astrocytes and granulocyte infiltration in the brain. KTX2 increases the production of the anti-inflammatory cytokine IL-10 and attenuates the activation of NFκB. KTX2 counterbalances cuprizone-induced brain unbalance of neurochemical redox parameters.

SKAP2 suppresses inflammation-mediated tumorigenesis by regulating SHP-1 and SHP-2.

Inflammatory bowel diseases, like ulcerative colitis and Crohn's disease are frequently accompanied by colorectal cancers. However, the mechanisms underlying colitis-associated cancers are not fully understood. Src Kinase Associated Phosphoprotein 2 (SKAP2), a substrate of Src family kinases, is highly expressed in macrophages. Here, we examined the effects of SKAP2 on inflammatory responses in a mouse model of tumorigenesis with colitis induced by azoxymethane/dextran sulfate sodium. SKAP2 knockout increased the severity of colitis and tumorigenesis, as well as lipopolysaccharide (LPS) induced acute inflammation. SKAP2 attenuated inflammatory signaling in macrophages induced by uptake of cancer cell-derived exosomes. SKAP2-/- mice were characterized by the activation of NF-κB signaling and the upregulation and release of cytokines including TNFα, IL-1β, IL-6, CXCL-9/-10/-13, and sICAM1; SKAP2 overexpression attenuated NF-κB activation. Mechanistically, SKAP2 formed a complex with the SHP-1 tyrosine phosphatase via association with the Sirpα transmembrane receptor. SKAP2 also physically associated with the TIR domain of MyD88, TIRAP, and TRAM, adaptors of toll-like receptor 4 (TLR4). SKAP2-mediated recruitment of the Sirpα/SHP-1 complex to TLR4 attenuated inflammatory responses, whereas direct interaction of SKAP2 with SHP-2 decreased SHP-2 activation. SHP-2 is required for efficient NF-κB activation and suppresses the TRAM/TRIF-INFβ pathway; therefore, SKAP2-mediated SHP-2 inhibition affected two signaling axes from TLR4. The present findings indicate that SKAP2 prevents excess inflammation by inhibiting the TLR4-NF-κB pathway, and it activates the TLR4-IFNβ pathway through SHP-1 and SHP-2, thereby suppressing inflammation-mediated tumorigenesis.