IL-1β activates p44/42 and p38 mitogen-activated protein kinases via different pathways in cat esophageal smooth muscle cells

AIM： To examine the pathway related to the IL-1β induced activation of mitogen-activated protein （MAP） kinases in cat esophageal smooth muscle cells. METHODS： Culture of the esophageal smooth muscle cells from cat was prepared. Specific inhibitors were treated before applying the IL-β3. Western blot analysis was performed to detect the expressions of COX, iNOS and MAP kinases. RESULTS： In the primary cultured cells, although IL-β3 failed to upregulate the COX and iNOS levels, the levels of the phosphorylated forms of 1344142 HAP kinase and p38 MAP kinase increased in both concentration- and time-dependent manner, of which the level of activation reached a maximum within 3 and 18 h, respectively. The pertussis toxin reduced the level of p44/42 MAP kinase phosphorylation. Tyrphostin 51 and genistein also inhibited this activation. Neomycin decreased the density of the p44/42 HAP kinase band to the basal level. Phosphokinase C （PKC） was found to play a mediating role in the IL-1β-induced p44/42 MAP kinase activity. In contrast, the activation of p38 MAP kinase was inhibited only by a pretreatment with forskolin, and was unaffected by the other compounds. CONCLUSION： Based on these results, IL-1β-induced p44/42 MAP kinase activation is mediated by the Gi protein, tyrosine kinase, phospholipase C （PLC） and PKC. The pathway for p38 MAP kinase phosphorylation is different from that of p44/42 MAP kinase, suggesting that it plays a different role in the cellular response to IL- 1β.

Small extracellular vesicles from hypoxia-preconditioned bone marrow mesenchymal stem cells attenuate spinal cord injury via miR-146a-5p-mediated regulation of macrophage polarization

Spinal cord injury is a disabling condition with limited treatment options.Multiple studies have provided evidence suggesting that small extracellular vesicles(SEVs)secreted by bone marrow mesenchymal stem cells(MSCs)help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury.Strikingly,hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs(HSEVs)exhibit increased therapeutic potency.We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair.SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation.HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation.HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro.Micro RNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that mi R-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1.Reducing mi R-146a-5p expression in HSEVs partially attenuated macrophage polarization.Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting mi R-146a-5p,which alters macrophage polarization.This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.

Inosine:A broad-spectrum anti-inflammatory against SARS-CoV-2 infection-induced acute lung injury via suppressing TBK1 phosphorylation

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)-induced cytokine storms constitute the primary cause of coronavirus disease 19(COVID-19)progression,severity,criticality,and death.Glucocorticoid and anti-cytokine therapies are frequently administered to treat COVID-19,but have limited clinical efficacy in severe and critical cases.Nevertheless,the weaknesses of these treatment modalities have prompted the development of anti-inflammatory therapy against this infection.We found that the broad-spectrum anti-inflammatory agent inosine downregulated proinflammatory interleukin(IL)-6,upregulated anti-inflammatory IL-10,and ameliorated acute inflammatory lung injury caused by multiple infectious agents.Inosine significantly improved survival in mice infected with SARS-CoV-2.It indirectly impeded TANK-binding kinase 1(TBK1)phosphorylation by binding stimulator of interferon genes(STING)and glycogen synthase kinase-3β(GSK3β),inhibited the activation and nuclear translocation of the downstream transcription factors interferon regulatory factor(IRF3)and nuclear factor kappa B(NF-κB),and downregulated IL-6 in the sera and lung tissues of mice infected with lipopolysaccharide(LPS),H1N1,or SARS-CoV-2.Thus,inosine administration is feasible for clinical anti-inflammatory therapy against severe and critical COVID-19.Moreover,targeting TBK1 is a promising strategy for inhibiting cytokine storms and mitigating acute inflammatory lung injury induced by SARS-CoV-2 and other infectious agents.

Interleukin-1 receptor associated kinase 2 is a functional downstream regulator of complement factor D that controls mitochondrial fitness in diabetic cardiomyopathy

Diabetic cardiomyopathy is a disorder of the cardiac muscle that affects patients with diabetes.The exact mechanisms underlying diabetic cardiomyopathy are mostly unknown,but several factors have been implicated in the pathogenesis of the disease and its progression towards heart failure,including endothelial dysfunction,autonomic neuropathy,metabolic alterations,oxidative stress,and alterations in ion homeostasis,especially calcium transients[1].In Military Medical Research,Jiang et al.[2]sought to determine the functional role of complement factor D(Adipsin)in the pathophysiology of diabetic cardiomyopathy.

Efficacy of Sishen Wan(四神丸) on dinitrobenzene sulfonic acid-induced ulcerative colitis and its effect on toll-like receptor 2/interleukin-1 receptor-associated kinase-4/nuclear factor-κB signal pathway

OBJECTIVE:To investigate the therapeutic effect of Sishen Wan(四神丸,SSW)on ulcerative colitis(UC)induced by dinitrobenzene sulfonic acid and its effect on toll-like receptor 2/interleukin-1 receptor-associated kinase-4/nuclear factor-κB(TLR2/IRAK4/NF-κB)signaling pathway in colonic tissue.METHODS:In this study,120 Sprague–Dawley rats were randomly divided into blank and model groups.The experimental UC model in rats was established by subcutaneous injection of hydrocortisone+senna gavage for 21 d+dinitrobenzene sulfonic acid(DNBS)/ethanol solution enema.The successful model rats were randomly divided into the model group;mesalazine(0.36 g/kg)group;and high-,medium-,and low-dose SSW(24,12,and 6 g/kg)groups.The model and blank groups were gavaged with equal volumes of distilled water once a day for 21 d.The general condition of the rats was observed,and the body mass,fecal properties,and occult blood were recorded for calculating the disease activity index(DAI)score.The colonic tissue of the rats was collected,and its general morphology and pathological form were noted for obtaining the colonic mucosal injury index(CMDI)score.Hematoxylin-eosin staining was used to view the pathological changes of the colon tissue in each group,apoptosis of the cells was detected using terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling staining,and quantitative real-time polymerase chain reaction was used to measure the expressions of TLR2,myeloid differentiation primary response gene 88(My D88),IRAK4,and NF-κB p65 mRNA in the colon tissue.The expressions of TLR2,My D88,IRAK4,and NF-κB p65 protein were detected using western blotting and immunohistochemistry assay,and the levels of interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)in the colon tissue were determined using enzyme linked immunosorbent assay.RESULTS:Compared with the blank group,the general condition of the model group was relatively poor.The DAI and CMDI scores of the model group increased significantly(P<0.01),the glands and intestinal mucosa disappeared partially,and several inflammatory cells infiltrated and gathered in the mucosal layer and base layer of the rats in the model group.Furthermore,the cell apoptosis and expression levels of TLR2,My D88,IRAK4,and NF-κB p65 mRNA and protein in the colon tissue of rats in the model group increased significantly(P<0.01).The levels of IL-1βand TNF-αincreased significantly in the colon tissue of rats in the model group(P<0.01).After treatment with SSW,compared with the model group,the general condition of the UC rats improved.Moreover,the DAI and CMDI scores of the UC rats decreased significantly(P<0.05),and the pathological changes in the colon tissue of the UC rats tended to be normal.The cell apoptosis and expression levels of TLR2,My D88,IRAK4,and NF-κB p65 mRNA and protein in the colon tissue of the UC rats decreased gradually(P<0.01),and the levels of IL-1βand TNF-αdecreased significantly(P<0.01).CONCLUSION:SSW can improve the general condition and alleviate the intestinal mucosal injury of UC model rats.Additionally,SSW can inhibit the TLR2/IRAK4/NF-κB signaling pathway,but further studies are required to confirm it.

Functional polymorphism in exon 5 and variant haplotype of the interleukin-1 receptor-associated kinase 1 gene are associated with susceptibility to and severity of sepsis in the Chinese population

Background The interleukin-1 （IL-1） receptor-associated kinase 1 （IRAK1） is believed to play an important role in the pathogenesis of sepsis. Recent studies have suggested that the I RAK1 functional genetic variant could affect the severity of sepsis in Caucasians. In this report, we have investigated whether polymorphisms at the IRAK1 gene are associated with the susceptibility to and severity of sepsis among the Chinese population. Methods Haplotype-tagging single nucleotide polymorphisms （htSNPs） were selected from the HapMap database. They.were genotyped in 255 patients with sepsis and 260 control subjects by PCR/restriction fragment length polymorphism （RFLP） analysis. The association between the selected htSNPs and the susceptibility to and severity of sepsis were estimated by Logistic regression with adjustments for age, sex, smoking, drinking, chronic disease status, Acute Physiology and Chronic Health Evaluation （APACHE） II score and primary diseases. Results rs1059702 was selected to represent the six linked htSNPs for IRAKI. Genotype frequencies of the htSNPs were in Hardy-Weinberg equilibrium for females, as were allele frequencies for both sex groups. Associations were observed in females between the htSNPs C/C genotype and increased susceptibility to sepsis （odds ratio （OR）, 5.46; 95% confidence interval （C/）, 1.12-26.67; P=0.018）, and such associations were also observed between the IRAK1 variant haplotype （CC/C-allele） and increased susceptibility to sepsis （OR, 1.68; 95% C/, 1.05-2.70; P=0.031） when compared with the T/T ＋ T/C genotype and the wild-type haplotype （TC ＋ TT/T-allele）. In the multiple organ dysfunction syndrome （MODS） subgroup, the variant haplotype was also associated with increased severity of sepsis （OR, 2.37; 95% Cl, 1.13-4.94; P=-0.02） when compared with the wild haplotype. This association was not significant in male patients. Conclusions The functional polymorphism in exon 5 and the variant haplotype of IRAK1 gene mediate susceptibility to and severity of sepsis. IRAK1 might be a genetic risk factor for the occurrence and development of sepsis in the Chinese population.

Regulatory Effects of AT1R-TRAF6-MAPKs Signaling on Proliferation of Intermittent Hypoxia-induced Human Umbilical Vein Endothelial Cells

Summary： Endothelial dysfunction induced by intermittent hypoxia （IH） participates in obstructive sleep apnea syndrome （OSAS）-associated cardiovascular disorders. Myeloid differentiation primary response 88 （MyD88） and tumor necrosis factor receptor-associated factor 6 （TRAF6） regulate nu- merous downstream adaptors like mitogen-activated protein kinases （MAPKs） and the subsequent oxidative stress and inflammatory responses. This study aimed to characterize the role of MyD88/TRAF6 in IH-treated cell function and its associated signaling. Human umbilical vein endo- thelial cells （HUVECs） were randomly exposed to IH or normoxia for 0, 2, 4 and 6 h. Western blot- ting was used to detect the expression pattern of target gene proteins [angiotensin 1 receptor （AT1R）, p-ERK1/2, p-p38MAPK, MyD88 and TRAF6], and the relationships among these target genes down-regulated by the corresponding inhibitors were studied. Finally, the influence of these target genes on proliferation of HUVECs was also assessed by EdU analysis. Protein levels of AT1R, TRAF6 and p-ERK1/2 were increased after IH exposure, with a slight rise in MyD88 and a dynamic change in p-p38MAPK. The down-regulation of TRAF6 by siRNA reduced ERK1/2 phosphorylation during IH without any effects on ATIR. Blockade of AT1R with valsartan decreased TRAF6 and p-ERK1/2 protein expression after IH exposure. ERK1/2 inhibition with PD98059 suppressed only AT1R expression. IH promoted HUVECs proliferation, which was significantly suppressed by the in- hibition of TRAF6, AT1R and ERK1/2. The findings demonstrate that TRAF6 regulates the prolifera- tion of HUVECs exposed to short-term IH by modulating cell signaling involving ERK1/2 down- stream of AT1R. Targeting the AT1R-TRAF6-p-ERK1/2 signaling pathway might be helpful in re- storing endothelial function.

Correlation of IRAK1 and TRAF6 expression with inflammatory response and immune response in oral lichen planus lesions

Objective: To study the correlation of IRAK1 and TRAF6 expression with inflammatory response and immune response in oral lichen planus lesions. Methods: Patients who were diagnosed with oral lichen planus in Ziyang First People's Hospital between June 2014 and February 2017 were selected as the OLP group of the study, and the oral lichen planus lesions were collected;42 patients who accepted surgery for oral trauma or maxillofacial plastic surgery were selected as the control group of the study, and the normal oral mucosa tissue was collected. The expression of IRAK1, TRAF6 and TLR4 signaling pathway molecules, Th1/Th2/Treg/Th17 transcription factors and cytokines in tissue samples were detected. Results:IRAK1, TRAF6, TLR4, MyD88 and NF-kB mRNA expression and protein expression in oral lichen planus lesions of OLP patients were significantly lower than those of control group, T-bet and IFN-γ levels were significantly lower than those of control group, and GATA3, FOXP3, RORγt, IL-4, IL-10 and IL-17 levels were significantly higher than those of control group;IRAK1 and TRAF6 expression in oral mucosa tissue were positively correlated with TLR4, MyD88 and NF-kB expression as well as T-bet and IFN-γ levels, and were negatively correlated with GATA3, FOXP3, RORγt, IL-4, IL-10 and IL-17 levels. Conclusion: IRAK1 and TRAF6 expression in oral lichen planus lesions can inhibit the TLR4 inflammatory response pathway and lead to Th1/Th2 /Treg/Th17 immune response disorder.

Flagellin of Pseudomonas aeruginosa induces transforming growth factor beta 1 expression in normal bronchial epithelial cells through mitogen activated protein kinase cascades

Background Acute lung infection due to Pseudomonas aeruginosa （P. Aeruginosa） is a serious problem, especially in patients with structural lung conditions or immune compromised hosts, leading to an overwhelming threat with a high risk of morbidity and mortality. As an outcome of infection, fibrosis can be linked with chronic lung diseases. But some fibrotic manifestations, such as an irreversible decrease of lung function and fibrous bands seen on chest imaging, have been found after an acute infection with P. Aeruginosa. Fibrogenesis/remodeling resulting from acute lung infection by P.aeruginosa is rarely reported. This study was designed to explore the relation between fibrogenesis/remodeling and acute infection by P. Aeruginosa in vitro. We used flagellin protein from P. Aeruginosa, a key initiator of acute P.aeruginosa lung infection, to elucidate mechanisms by which acute lung infection with P. Aeruginosa can cause fibrogenesis/remodeling.Methods We studied the effect of flagellin from P. Aeruginosa （flagellin for short） on the transforming growth factor beta 1 （TGF-β1） and interleukin-8 （IL-8） expression, and the possible involvement of the signaling pathway, tumor necrosis factor receptor-associated factor 6 （TRAF6）/mitogen activated protein kinase （MAPK） pathway. Flagellin was purified from the P. Aeruginosa standard strain, PAO1. Normal bronchial epithelial cells BEAS-2B were challenged with different concentrations of flagellin, and cell viability assessment was performed by cell counting kit-8. BEAS-2B cells were incubated with flagellin with the specific MAPK inhibitors or TRAF6 siRNA. Cell lysates and the cultured supernatant were collected. The level of TGF-β1 and IL-8 were detected by enzyme-linked immunosorbant assay （ELISA）. Western blotting was used to detect the protein levels of MAPK signal proteins p38, c-Jun NH2-terminal kinase （JNK） and extracellular regulated kinase （ERK）.Results Expression of TGF-β1 in BEAS-2B cells was elevated by flagellin vs. Control groups （（104.3±20.8） vs.（44.6±4.4） pg/ml （P 〈0.01）） and was ablated by either p38 or JNK inhibitors compared with flagellin treatment （（45.1±18.8）vs. （104.3±20.8） pg/ml and （48.1±20.8） vs. （104.3±20.8） pg/ml, respectively （P 〈0.05））. Flagellin also elevated the expression of IL-8 in BEAS-2B cells vs. The control groups （（554.9±57.7） vs. （51.4±2.2.9） pg/ml （P 〈0.01））, and p38 MAPK inhibitors weaken the expression by flagellin （（301.1 ±155.1） vs. （554.9±57.7） pg/ml （P 〈0.05））. Western blotting revealed that all three MAPK proteins, p38, JNK and ERK were activated by flagellin challenge in an early phase, respectively in 15 minutes （P 〈0.01）, 30 minutes （P 〈0.01） and 15 minutes （P 〈0.01）. TRAF6 siRNA which decreased expression of TRAF6, altered the activation of JNK, p38, and ERK following flagellin treatment, but its influence on the expression of TGF-β1 and IL-8 has no statistical significance.Conclusions Flagellin from P. Aeruginosa PAO1 induces TGF-β1 expression in normal bronchial epithelial cells,BEAS-2B, through the MAPK signal cascade in vitro. It suggests that the fibrogenesis/remodeling process may be initiated from an early stage of acute lung infection due to P. Aeruginosa.

Potential mechanisms of hepatitis B virus induced liver injury

Chronic active hepatitis(CAH) is acknowledged as an imperative risk factor for the development of liver injury and hepatocellular carcinoma.The histological end points of CAH are chronic inflammation,fibrosis and cirrhosis which are coupled with increased DNA synthesis in cirrhotic vs healthy normal livers.The potential mechanism involved in CAH includes a combination of processes leading to liver cell necrosis,inflammation and cytokine production and liver scaring(fibrosis).The severity of liver damage is regulated by Hepatitis B virus genotypes and viral components.The viral and cellular factors that contribute to liver injury are discussed in this article.Liver injury caused by the viral infection affects many cellular processes such as cell signaling,apoptosis,transcription,DNA repair which in turn induce radical effects on cell survival,growth,transformation and maintenance.The consequence of such perturbations is resulted in the alteration of bile secretion,gluconeogenesis,glycolysis,detoxification and metabolism of carbohydrates,proteins,fat and balance of nutrients.The identification and elucidation of the molecular pathways perturbed by the viral proteins are important in order to design effective strategy to minimize and/or restore the hepatocytes injury.

Caspase-1 activation by NLRP3 inflammasome dampens IL-33-dependent house dust mite-induced allergic lung inflammation

The cysteine protease caspase-1(Casp-1)contributes to innate immunity through the assembly of NLRP3,NLRC4,AIM2,and NLRP6 inflammasomes.Here we ask whether caspase-1 activation plays a regulatory role in house dust mite(HDM)-induced experimental allergic airway inflammation.We report enhanced airway inflammation in caspase-1-deficient mice exposed toHDMwith a marked eosinophil recruitment,increased expression of IL-4,IL-5,IL-13,aswell as full-length and bioactive IL-33.Furthermore,mice deficient for NLRP3 failed to control eosinophil influx in the airways and displayed augmented Th2 cytokine and chemokine levels,suggesting that the NLPR3 inflammasome complex controls HDM-induced inflammation.IL-33 neutralization by administration of soluble ST2 receptor inhibited the enhanced allergic inflammation,while administration of recombinant IL-33 during challenge phase enhanced allergic inflammation in caspase-1-deficient mice.Therefore,we show that caspase-1,NLRP3,and ASC,but not NLRC4,contribute to the upregulation of allergic lung inflammation.Moreover,we cannot exclude an effect of caspase-11,because caspase-1-deficient mice are deficient for both caspases.Mechanistically,absence of caspase-1 is associated with increased expression of IL-33,uric acid,and spleen tyrosine kinase(Syk)production.This study highlights acritical role of caspase-1 activation andNLPR3/ASCinflammasomecomplex in the down-modulation of IL-33 in vivo and in vitro,thereby regulating Th2 response in HDM-induced allergic lung inflammation.

Regulation of CD137 expression through K-Ras signaling in pancreatic cancer cells

Background:The interaction between CD137 and its ligand(CD137L)plays a major role in the regulation of immune functions and affects cancer immunotherapy.CD137 is a cell surface protein mainly located on activated T cells,and its regulation and functions in immune cells are well established.However,the expression of CD137 and its regulation in cancer cells remain poorly understood.The main purposes of this study were to examine the expression of CD137 in pancreatic cancer cells and to investigate its underlying mechanisms.Methods:Cells containing inducible K-RasG12V expression vector or with different K-Ras mutational statuses were used as in vitro models to examine the regulation of CD137 expression by K-Ras.Various molecular assays were employed to explore the regulatory mechanisms.Tumor specimens from 15 pancreatic cancer patients and serum samples from 10 patients and 10 healthy donors were used to test if the expression of CD137 could be validated in clinical samples.Results:We found that the CD137 protein was expressed on the cell surface in pancreatic cancer tissues and cancer cell lines.Enzyme-linked immunosorbent assay revealed no difference in the levels of secreted CD137 in the sera of patients and healthy donors.By using the K-Ras inducible cell system,we further showed that oncogenic K-Ras up-regulated CD137 through the activation of MAPK(mitogen-activated protein kinases)and NF-κB(nuclear factor kappa-light-chain-enhancer of activated B cells)pathways,as evidenced by significantly reduced CD137 mRNA expression led by genetic silencing of MAPK1 and p65,the key proteins involved in the respective pathways.Further-more,we also found that the NF-κB pathway was mainly stimulated by the K-Ras-induced secretion of interleukin-1α(IL-1α)which promoted the transcription of the CD137 gene in pancreatic cancer cell lines.Analysis of the TCGA(the cancer genome atlas)database also revealed a significant correlation between IL-1αand CD137 expression(r=0.274)in tumor samples from pancreatic cancer patients(P<0.001).Conclusions:The present study has demonstrated that the CD137 protein was expressed on pancreatic cancer cell surface,and has identified a novel mechanism by which K-Ras regulates CD137 in pancreatic cancer cells through MAPK and NF-κB pathways stimulated by IL-1α.

Celastrol targets IRAKs to block Toll-like receptor 4-mediated nuclear factor-κB activation

OBJECTIVE： Celastrol has been established as a nuclear factor-κB（NF-κB） activation inhibitor; however, the exact mechanism behind this action is still unknown. Using text-mining technology, the authors predicted that int erleukin-1 receptor-associated kinases（IRA Ks） are potential celastrol targets, and hypothesized that targeting IRAKs might be one way that celastrol inhibits NF-κB. This is because IRAKs are key molecules for some crucial pathways to activate NF-κB（e.g., the inter leukin-1 receptor（IL-1R）/Toll- like receptor（TLR） superfamily）.METHODS： The human hepatocellular cell line（Hep G2） treated with palmitic acid（PA） was used as a model for stimulating TLR4/NF-κB activation, in order to observe the potential effects of celastrol in IRAK regulation and NF-κB inhibition. The transfection of small interfering RNA was used for down-regulating TLR4, IRAK1 and IRAK4, and the Western blot method was used to detect changes in the protein expressions.RESULTS： The results showed that celastrol could effectively inhibit PA-caused TLR4-dependent NF-κB activation in the Hep G 2 cells; PA also activated IRAKs, which were inhibited by celastrol. Knocking down IRAKs abolished PA-caused NF-κB activation.CONCLUSION： The results for the first time show that targeting IRAKs is one way in which celastrol inhibits NF-κB activation.