A20 overexpression inhibits lipopolysaccharide-induced NF-κB activation, TRAF6 and CD40 expression in rat peritoneal mesothelial cells

Bavachin exerted anti-neuroinflammatory effects by regulation of A20 ubiquitin-editing complex

Neuroinflammation is a major pathophysiological contributor to the progression of the central nervous system disorders. Bavachin is a natural product belonging to the flavonoid class. The anti-neuroinflammatory effect and the molecular mechanisms are not well understood. In this study, we found bavachin can exert anti-neuroinflammatory effect via inhibition of nuclear factor-kappa B (NF-κB) signaling. We found that bavachin can obviously upregulate the expression of A20 (TNFAIP3) in microglial cells. Further studies suggested siRNA-A20 knockdown treatment can attenuate the inhibitory effects of bavachin on neuroinflammation. We further found bavachin can increase the interaction of ubiquitin-editing enzyme A20 complex including A20, Tax1-binding protein 1 (TAX1BP1) and Itch, the subsequently downregulated the K63-ubiquitination of TNF receptor associated factor 6 (TRAF6) and NF-κB signaling pathway. Altogether, our results indicated that bavachin exerted anti-neuroinflammatory effects through inhibition of NF-κB signaling mediated by regulation of ubiquitin-editing enzyme A20 complex. Our finding has important clinical significance for the potential application of bavachin in the treatment of neurological disorders.

Mutation analysis of the TNFAIP3 in A20 haploinsufficiency: A case report

INTRODUCTION

Haploinsufficiency of A20 (HA20) is a novel genetic disease presented by Zhou et al in 2016. A20 is a protein encoded by TNFAIP3. Loss-of-function mutation in TNFAIP3 will trigger a new autoinflammatory disease: HA20. HA20-affected patients may develop a wide range of clinical manifestations, such as Behcet disease, rheumatoid arthritis, rheumatic fever, juvenile idiopathic arthritis, and systemic lupus erythematosus. HA20 is rarely reported, thus remaining far from thoroughly understood. Sixty-one cases of HA20 have been reported worldwide, among which 29 cases were diagnosed with Behcet disease ultimately. Moreover, 3 cases have been reported in China, which was the first report of HA20 characterized by Behcet disease. A comprehensive understanding of the pathogenic genes of HA20 could help us apply targeted therapy as soon as possible to improve patients' survival rates.

PATIENT CONCERNS

A 2-year-old 3-month-old child was presented to our hospital with recurrent infectious enteritis and stomatitis.

DIAGNOSIS

Genetic mutations were detected immediately, and a novel pathogenic mutation was found in TNFAIP3. A heterozygous mutation (c.436-437deTC) located at TNFAIP3 was confirmed. The present research indicated that the TNFAIP3 mutation of c.436-437deTC (p.L147Qfs∗7) accounted for familial Behcet-like autoinflammatory syndrome in the child suffering from HA20, while no variation in this locus was found in her parents.

INTERVENTIONS

Symptomatic treatments including oral administration of prednisone (12.5 mg/d) and iron supplement were performed, and repeated infection was no longer observed in the child. Pain and activity limitation was found in the knee joints. The treatment regimen was adjusted to oral prednisone (12.5 mg/dose, 2 doses/d) and subcutaneous injection of rhTNFR:Fc (12.5 mg/week).Outcomes: At the last follow-up, the limbs' activities were normal, the inflammatory indicators were reduced or within the normal range. The prednisone dose was reduced to 7.5 mg/d, while the dose of rhTNFR:Fc was not changed.

CONCLUSION

We have identified a novel pathogenic HA20 mutation. In this article, 1 case was analyzed in-depth in terms of clinical manifestations of the patient and new sources of such a novel disease, which might improve our understanding of this disease.

Prominence of IL6, IGF, TLR, and Bioenergetics Pathway Perturbation in Lung Tissues of Scleroderma Patients With Pulmonary Fibrosis

Scleroderma-associated pulmonary fibrosis (SSc-PF) and idiopathic pulmonary fibrosis (IPF) are two of many chronic fibroproliferative diseases that are responsible for nearly 45% of all deaths in developed countries. While sharing several pathobiological characteristics, they also have very distinct features. Currently no effective anti-fibrotic treatments exist that can halt the progression of PF or reverse it. Our goal is to uncover potential gene targets for the development of anti-fibrotic therapies efficacious in both diseases, and those specific to SSc-PF, by identifying universal pathways and molecules driving fibrosis in SSc-PF and IPF tissues as well as those unique to SSc-PF. Using DNA microarray data, a meta-analysis of the differentially expressed (DE) genes in SSc-PF and IPF lung tissues (diseased vs. normal) was performed followed by a full systems level analysis of the common and unique transcriptomic signatures obtained. Protein-protein interaction networks were generated to identify hub proteins and explore the data using the centrality principle. Our results suggest that therapeutic strategies targeting IL6 trans-signaling, IGFBP2, IGFL2, and the coagulation cascade may be efficacious in both SSc-PF and IPF. Further, our data suggest that the expression of matrikine-producing collagens is also perturbed in PF. Lastly, an overall perturbation of bioenergetics, specifically between glycolysis and fatty acid metabolism, was uncovered in SSc-PF. Our findings provide insights into potential targets for the development of anti-fibrotic therapies that could be effective in both IPF and SSc-PF.

Pistacia weinmannifolia root exerts a protective role in ovalbumin‑induced lung inflammation in a mouse allergic asthma model

Pistacia weinmannifolia (Anacardiaceae) has been used in herbal medicine for the treatment of influenza, dysentery and enteritis in China. It was recently observed that P. weinmannifolia root extract (PWRE) exerts anti‑inflammatory effects both in in vitro and in vivo models. Based on the results from previous studies, the present study investigated the protective effect of PWRE on airway inflammation and mucus hypersecretion. Treatment with PWRE significantly decreased the number of eosinophils and the levels of Th2 cytokines, such as interleukin (IL)‑4, IL‑5 and IL‑13, in the bronchoalveolar lavage fluid (BALF) of OVA‑exposed mice. PWRE decreased the high serum levels of total and OVA‑specific immunoglobulin E. PWRE also effectively inhibited the influx of inflammatory cells into the lung, as well as airway mucus hypersecretion. In addition, the increased level of monocyte chemoattractant protein‑1 was significantly decreased with the PWRE treatment in the BALF of OVA‑exposed mice and in lipopolysaccharide‑stimulated RAW264.7 macrophages. These protective effects of PWRE on OVA‑induced pulmonary inflammation were accompanied by the downregulation of mitogen associated protein kinases and nuclear factor‑κB activation. Thus, the results from the present study indicate that PWRE could be valuable adjuvant for the treatment of asthma.

Berberine improves intestinal epithelial tight junctions by upregulating A20 expression in IBS-D mice

To investigate effects of berberine exerts on A20 expression and regulation of intestinal epithelial tight junctions via the TNF-α-NF-κB-MLCK pathway in Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D). C57BL/6 wild type (WT) and A20 IEC-KO mice (48 each) were randomly divided into normal control (NC), model control (MC), rifaximin and berberine groups (12 mice per group). An experimental model of IBS-D was established using 4% acetic acid and evaluated by haematoxylin-eosin (HE) staining. rifaximin and berberine mice were treated with rifaximin and berberine, respectively. Intestinal epithelial space of WT berberine mice improved more than A20 IEC-KO berberine mice compared to MC mice. WT berberine mice exhibited greater expression of A20 compared with MC mice(P < 0.01). TNF-α, NF-kB p65, MLCK, MLC, TRAF6 and RIP1 levels in A20 IEC-KO and WT berberine mice were all decreased compared to MC mice(P all<0.05). NF-κB p65, MLCK and TRAF6 levels were increased in A20 IEC-KO berberine mice as compared to WT berberine mice (P all<0.05). Intestinal epithelial levels of occludin, claudin-1, ZO-1 and F-actin increased in all berberine mice (P all<0.01-0.05), while occludin, claudin-1, and ZO-1 levels were lower in A20 IEC-KO berberine mice(P < 0.05). Berberine downregulates abnormal activation of the TNF-α-NF-κB-MLCK pathway by upregulating expression of A20 in a mouse model of IBS-D, thereby protecting intestinal epithelial tight junctions and repairing the damage IBS-D causes to the intestinal epithelial barrier.

A20 as a novel target for the anti-neuroinflammatory effect of chrysin via inhibition of NF-κB signaling pathway

Neuroinflammation is now recognized to be a feature of many neurological disorders. More accumulated evidences suggested chrysin which was contained in honey, propolis, vegetables, fruits and plants can exert biological activities including anti-neuroinflammatory effects. However, the precise molecular mechanisms of anti-neuroinflammatory effects remain unclear. In the present study, we explored a novel molecular mechanism involved in the anti-neuroinflammatory effect of chrysin. Firstly, we investigated the anti-neuroinflammatory effects of chrysin in LPS-induced BV2, primary microglial cells and mice. Next, we found chrysin can inhibit NF-κB pathway and TRAF6 expression, but upregulate the expression of zinc-finger protein A20. Further studies have revealed upregulation of A20 can regulate the inhibitory effects of chrysin on NF-κB pathways via regulation of TRAF6 polyubiquitination. This present study demonstrates that chrysin exerts an anti-neuroinflammatory effect via a novel mechanism, the upregulation of A20 expression, also validates A20 is a novel effective pharmacological target for developing agents in the treatment of neuroinflammation-related diseases.

Stroma: the forgotten cells of innate immune memory

All organisms are exposed constantly to a variety of infectious and injurious stimuli. These induce inflammatory responses tailored to the threat posed. While the innate immune system is the front line of response to each stimulant, it has been considered traditionally to lack memory, acting in a generic fashion until the adaptive immune arm can take over. This outmoded simplification of the roles of innate and acquired arms of the immune system has been challenged by evidence of myeloid cells altering their response to subsequent encounters based on earlier exposure. This concept of 'innate immune memory' has been known for nearly a century, and is accepted among myeloid biologists. In recent years other innate immune cells, such as natural killer cells, have been shown to display memory, suggesting that innate immune memory is a trait common to several cell types. During the last 30 years, evidence has slowly accumulated in favour of not only haematopoietic cells, but also stromal cells, being imbued with memory following inflammatory episodes. A recent publication showing this also to be true in epithelial cells suggests innate immune memory to be widespread, if under-appreciated, in non-haematopoietic cells. In this review, we will examine the evidence supporting the existence of innate immune memory in stromal cells. We will also discuss the ramifications of memory in long-lived tissue-resident cells. Finally, we will pose questions we feel to be important in the understanding of these forgotten cells in the field of innate memory.

Human umbilical cord mesenchymal stem cells facilitate the up-regulation of miR-153-3p, whereby attenuating MGO-induced peritoneal fibrosis in rats

MiRNAs contribute greatly to epithelial to mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs), which is a crucial step in peritoneal fibrosis (PF). In this study, we tried to profile whether miRNA expression differences exist after human umbilical cord mesenchymal stem cells (hUCMSCs) treatment in PF rats and investigate the possible role of miR‐153‐3p involved in anti‐EMT process. We randomly assigned 34 rats into three groups: control group (Group Control), MGO‐induced PF rats (Group MGO) and hUCMSCs‐treated rats (Group MGO + hUCMSCs). MiRNA microarrays and real‐time PCR analyses were conducted in three groups. α‐SMA, Snail1 and E‐cadherin expression were detected by Western blot. Luciferase reporter assays were used to detect the effects of miR‐153‐3p overexpression on Snai1 in rat peritoneal mesothelial cells (RPMCs). We identified differentially expressed miRNAs related to EMT, in which miR‐153‐3p demonstrated the greatest increase in Group MGO + hUCMSCs. Transient cotransfection of miR‐153‐3p mimics with luciferase expression plasmids resulted in a significant repression of Snai1 3′‐untranslated region luciferase activity in RPMCs. These studies suggest that miR‐153‐3p is a critical molecule in anti‐EMT effects of hUCMSCs in MGO‐induced PF rats. MiR‐153‐3p might exert its beneficial effect through directly targeting Snai1.

Antimicrobial Peptide Epinecidin-1 Modulates MyD88 Protein Levels via the Proteasome Degradation Pathway

The cationic antimicrobial peptide epinecidin-1 was identified from Epinephelus coioides and possesses multiple biological functions, including antibacterial, antifungal, anti-tumor, and immunomodulatory effects. In addition, epinecidin-1 suppresses lipopolysaccharide (LPS)-induced inflammation by neutralizing LPS and ameliorating LPS/Toll-like receptor (TLR)-4 internalization. However, it is unclear whether the actions of epinecidin-1 depend on the regulation of TLR adaptor protein MyD88 or endogenous TLR signaling antagonists, which include A20, interleukin-1 receptor associated kinase (IRAK)-M, and suppressor of cytokine signaling (SOCS)-1. Our results demonstrate that epinecidin-1 alone does not affect A20, IRAK-M, or SOCS-1 protein levels. However, pre-incubation of epinecidin-1 significantly inhibits LPS-induced upregulation of A20, IRAK-M, and SOCS-1. In addition, epinecidin-1 significantly reduces the abundance of MyD88 protein. Both MG132 (a specific proteasome inhibitor) and Heclin (a specific Smurf E3 ligase inhibitor) are able to abolish epinecidin-1-mediated MyD88 degradation. Thus, our data suggest that epinecidin-1 directly inhibits MyD88 via induction of the Smurf E3 ligase proteasome pathway.

Polydatin inhibits mast cell-mediated allergic inflammation by targeting PI3K/Akt, MAPK, NF-κB and Nrf2/HO-1 pathways

Polydatin(PD) shows anti-allergic inflammatory effect, and this study investigated its underlying mechanisms in in vitro and in vivo models. IgE-mediated passive cutaneous anaphylaxis (PCA) and passive systemic anaphylaxis (PSA) models were used to confirm PD effect in vivo. Various signaling pathway proteins in mast cell were examined. RT-PCR, ELISA and western blotting were applied when appropriate. Activity of Lyn and Fyn kinases in vitro was measured using the Kinase Enzyme System. PD dose-dependently reduced the pigmentation of Evans blue in the PCA model and decreased the concentration of serum histamine in PSA model, and attenuated the degranulation of mast cells without generating cytotoxicity. PD decreased pro-inflammatory cytokine expression (TNF-α, IL-4, IL-1β, and IL-8). PD directly inhibited activity of Lyn and Syk kinases and down-regulated downstream signaling pathway including MAPK, PI3K/AKT and NF-kB. In addition, PD also targets Nrf2/HO-1 pathway to inhibit mast cell-derived allergic inflammatory reactions. In conclusion, the study demonstrates that PD is a possible therapeutic candidate for allergic inflammatory diseases. It directly inhibited activity of Lyn and Syk kinases and down-regulates the signaling pathway of MAPK, PI3K/AKT and NF-κB, and up-regulates the signaling pathway of Nrf2/HO-1 to inhibit the degranulation of mast cells.

Di-(2-ethylhexyl) phthalate suppresses IL-12p40 production by GM-CSF-dependent macrophages via the PPARα/TNFAIP3/TRAF6 axis after lipopolysaccharide stimulation

Activation of peroxisome proliferator-activated receptor α (PPARα) by di-(2-ethylhexyl) phthalate (DEHP) has an anti-inflammatory effect. This study investigated the potential combined influence of PPARα, tumor necrosis factor α-induced protein 3 (TNFAIP3/A20), and tumor necrosis factor receptor-associated factor 6 (TRAF6) on interleukin (IL)-12p40 production by macrophages exposed to DEHP and stimulated with lipopolysaccharide (LPS). LPS upregulated IL-12p40 expression by granulocyte-macrophage colony-stimulating factor-dependent macrophages (on day 9 of culture), whereas adding DEHP to cultures significantly attenuated the response of IL-12p40 to LPS stimulation. PPARα protein was also reduced by DEHP. Interestingly, transfection of macrophages with small interfering RNA (siRNA) duplexes for PPARα, TNFAIP3/A20, or dual oxidase 2 restored the response of IL-12p40 protein to LPS stimulation in the presence of DEHP. siRNAs for various protein kinase Cs (PKCs) (α, β, γ, or δ) also restored IL-12p40 production by macrophages exposed to LPS and DEHP. While LPS upregulated both IL-12p40 and TNFAIP3/A20 production, adding DEHP to cultures dramatically reduced IL-12p40 and TNFAIP3/A20 levels. Silencing of PKCα reduced TNFAIP3/A20 production, whereas PKCγ siRNA (but not PKCβ or δ siRNA) significantly increased TNFAIP3/A20. TRAF6 was also attenuated by macrophages with DEHP. The PPARα/TNFAIP3/TRAF6 axis may have an important role in the mechanism through which DEHP reduces IL-12p40 production by LPS-stimulated macrophages.

The transfection of A20 gene prevents kidney from ischemia reperfusion injury in rats

Ischemia/reperfusion may induce inflammation and cell death through the nuclear factor (NF)‑κB signaling pathway. As a negative regulator of NF‑κB, zinc finger A20 exhibits anti-apoptotic and anti‑inflammatory effects in vitro. The present study was designed to upregulate A20 expression using an A20 transfection approach to investigate the in vivo protective effects of the A20 gene on renal ischemia reperfusion injury. The A20 gene was cloned into a pcDNA3.1 vector to construct the expression plasmid pcDNA3.1‑A20. The plasmid was wrapped with a liposome and injected intravenously into rats 48 h prior to establishing the models of renal ischemia reperfusion injury. Saline and the empty plasmid pcDNA3.1 were used as controls. Following 24 h post‑operation, A20 expression was determined using reverse transcription‑quantitative polymerase chain reaction and western blotting. The renal function and structure were assessed by analyzing the concentrations of serum creatinine (Scr), blood urea nitrogen (BUN) and histological features. Renal tissues were additionally examined for renal tubular cell apoptosis and NF‑κB activity. The results demonstrated that in vivo transfection of pcDNA3.1‑A20 induced renal A20 expression in rats. A20 overexpression in vivo significantly reduced renal injury as demonstrated by the improved levels of Scr and BUN and the reduction in histological damage. These improvements were accompanied by a suppression of renal proximal tubular epithelial cell apoptosis and an inhibition of NF‑κB activity. These results indicated that transfection of the A20 gene upregulates the expression of A20 in vivo and protects the kidneys from ischemia reperfusion injury via inhibition of the NF‑κB signal transduction pathway.

Macrophages produce IL-33 by activating MAPK signaling pathway during RSV infection

It has been reported that RSV infection can enhance IL-33 production in lung macrophages. However, little is known about specific signaling pathways for activation of macrophages during RSV infection. In the present study, by using real-time RT-PCR as well as western blot assay, it became clear that RSV infection can enhance not only the expression of mRNAs for MAPK molecules (including p38, JNK1/2, and ERK1/2), but also the levels of MAPK proteins in lung macrophages as well as RAW264.7 cells. Furthermore, infection with RSV resulted in an increased level of phosphorylated MAPK proteins in RAW264.7 cells, suggesting that MAPK signaling pathway may participate in the process of RSV-induced IL-33 secretion by macrophages. In fact, the elevated production of IL-33 in RAW264.7 was attenuated significantly by pretreatment of the cells with special MAPK inhibitor before RSV infection, further confirming the function of MAPKs pathway in RSV-induced IL-33 production in macrophages. In contrast, the expression of NF-κB mRNA as well as the production of NF-κB protein in lung macrophages and RAW264.7 cells was not enhanced markedly after RSV infection. Moreover, RSV infection failed to induce the phosphorylation of NF-κB in RAW264.7 cells, suggesting that NF-κB signaling pathway may be not involved in RSV-induced IL-33 production in macrophages. Conclusion, these results indicate that RSV-induced production of IL-33 in macrophages is dependent on the activation of MAPK signaling pathway.

Therapeutic effects of rosmarinic acid on airway responses in a murine model of asthma

Rosmarinic acid (RA) is an active component of a traditional Chinese herbal medicine. Previously, we reported that RA exerted a strong anti-inflammatory effect in a mouse acute lung injury model. Therefore, we hypothesized that RA might also have potential therapeutic effects in a murine model of asthma. In this study, we aimed to evaluate the anti-asthmatic activity of RA and explored its possible molecular mechanisms of action. Female BALB/c mice that had been sensitized to and challenged with ovalbumin (Ova) were treated with RA (20mg/kg) 1h after challenge. The results showed that RA greatly diminished the number of inflammatory cells and the production of Th2 cytokines in the bronchoalveolar lavage fluid (BALF); significantly reduced the secretion of total IgE, Ova-specific IgE, and eotaxin; and markedly ameliorated airway hyperresponsiveness (AHR) compared with Ova-induced mice. Histological studies further revealed that RA substantially decreased inflammatory cells infiltration and mucus hypersecretion compared with Ova-induced mice. Moreover, our results suggested that the protective effects of RA were mediated by the inhibition of JNK and p38 MAPK phosphorylation and nuclear factor-κB (NF-κB) activation. Furthermore, RA treatment resulted in a significant reduction in the mRNA expression of AMCase, CCL11, CCR3, Ym2 and E-selectin in lung tissue. These findings suggest that RA may effectively delay the development of airway inflammation and could thus be used as a therapy for allergic asthma.

Rosmarinic Acid Attenuates Airway Inflammation and Hyperresponsiveness in a Murine Model of Asthma

Rosmarinic acid (RA) has numerous pharmacologic effects, including anti-oxidant, anti-inflammatory, and analgesic effects. This study aimed to evaluate the preventive activity of RA in a murine model of asthma and to investigate its possible molecular mechanisms. Female BALB/c mice sensitized and challenged with ovalbumin (Ova) were pretreated with RA (5, 10 or 20 mg/kg) at 1 h before Ova challenge. The results demonstrated that RA markedly inhibited increases in inflammatory cells and Th2 cytokines in the bronchoalveolar lavage fluid (BALF), significantly reduced the total IgE and Ova-specific IgE concentrations, and greatly ameliorated airway hyperresponsiveness (AHR) compared with the control Ova-induced mice. Histological analyses showed that RA substantially decreased the number of inflammatory cells and mucus hypersecretion in the airway. In addition, our results suggested that the protective effects of RA might be mediated by the suppression of ERK, JNK and p38 phosphorylation and activation of nuclear factor-κB (NF-κB). Furthermore, RA pretreatment resulted in a noticeable reduction in AMCase, CCL11, CCR3, Ym2 and E-selectin mRNA expression in lung tissues. These findings suggest that RA may effectively delay the progression of airway inflammation.