Effect of NOD8 on production of nitric oxide,IL-1β and TNF-α in LPS-treated macrophages

AIM: To investigate the effect of NOD8 on lipopolysaccharide (LPS)-induced releases of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in RAW264.7 cells. METHODS: The plasmids of pEGFP-C2 and pEGFP-NOD8 were transfected into RAW264.7 cells respectively. The transfected and non-transfected cells were stimulated by LPS for 0, 6, 12 and 24 h. NO production was evaluated by Griess reagent assay, and the levels of IL-1β and TNF-α were measured by ELISA. The protein expression of NOD8 and the nuclear translocation of nuclear factor κB (NF-κB) p65 subunit were detected by Western blotting. The level of activated caspase-1 was determined by fluorimetric method. RESULTS: Compared with pEGFP-C2 group, the protein expression of NOD8 was significantly elevated in pEGFP-NOD8+LPS group. The releases of NO, IL-1β and TNF-α were obviously increased after RAW264.7 cells were treated with LPS for 6 h, 12 h and 24 h, and while the secretion of NO was significantly reduced in the cells transfected with pEGFP-NOD8 and induced by LPS for 12 h and 24 h, and the release of IL-1β was also significantly reduced at 6 h, 12 h and 24 h. However, no significant difference of TNF-α release was observed between pEGFP-C2+LPS group and pEGFP-NOD8+LPS group. The activation of caspase-1 in RAW264.7 cells stimulated with LPS for 6 h, 12 h and 24 h was markedly increased, and the expression of NF-κB p65 subunit in the cytoplasm was significantly decreased, indicating that p65 nuclear translocation was increased. In addition, the activation of caspase-1 and the nuclear translocation of p65 were significantly inhibited in pEGFP-NOD8+LPS group. CONCLUSION: NOD8 suppresses the releases of LPS-induced NO and IL-1β in RAW264.7 cells by inhibiting the activation of caspase-1 and NF-κB.     

Inhibitory effect of madecassoside on LPS-stimulated microglia

AIM: To observe the inhibitory effect of madecassoside on the LPS-stimulated microglia and to investigate its possible mechanism. METHODS: Microglia cells of neonatal Sprague-Dawley (SD) rats were cultured, isolated and purified. Microglia cells were activated with lipopolysaccharide (LPS). The inhibitory effect of madecassoside on microglia was measured by MTT assay. Tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β) were detected by ELISA. Cell cycle and apoptotic rate were evaluated by flow cytometry. The expression of TLR4 was detected by Western blotting. The expression of NF-κB was detected by RT-PCR. RESULTS: LPS induced the proliferation of microglia and release inflammatory cytokines significantly. Compared with LPS group, madecassoside inhibited the proliferation of microglia induced by LPS in a dose dependent manner. The IC₅₀ value of madecassoside was 10.97 nmol/L to microglia after incubation for 48 h. Madecassoside also decreased the levels of TNF-α and IL-6, increased the ratios of microglia at the G₂ phase and the apoptotic rate, decreased the expression of TLR4 and NF-κB significantly (P<0.05). CONCLUSION: Madecassoside has inhibitory effects on the proliferation of LPS-stimulated microglia, by which the mechanism may be related to inhibition of the expression of TLR4 and NF-κB, change of cell cycle distribution and induction of microglia apoptosis.     

Up-regulation of miR-181a attenuates releases of CSE-induced pro-inflammatory factors and expression of collagen IV,fibronectin and α-SMA in human bronchial epithelial cells

AIM: To investigate the effect and potential mechanism of microRNA-181a (miR-181a) on cigarette smoke extract (CSE)-induced the productions of pro-inflammatory factors and the expression of collagen IV, fibronectin and α-smooth muscle actin (α-SMA) in human bronchial epithelial cells (HBECs). METHODS: CSE-induced miR-181a expression was detected by RT-qPCR in the HBECs. After tansfected with miR-181a mimic, the releases of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and transforming growth factor-β1 (TGF-β1) were measured by ELISA, the protein expression of collagen IV, fibronectin and α-SMA was determined by Western blot. The activation of NF-κB/TGF-β1/Smad3 pathway was also evaluated by Western blot. RESULTS: CSE increased the levels of TNF-α, IL-1β, IL-6 and TGF-β1 and the expression of collagen IV, fibronectin and α-SMA, and decreased the expression of miR-181a in the HBECs (P<0.05). However, transfected with miR-181a mimic partially prevented the releases of TNF-α, IL-1β, IL-6 and TGF-β1, and inhibited the expression of collagen IV, fibronectin and α-SMA (P<0.05). Additionally, the activation of NF-κB/TGF-β1/Smad3 evoked by CSE was attenuated after transfected with miR-181a mimic. CONCLUSION: Up-regulation of miR-181a prevents the releases of CSE-induced pro-inflammatory factors and expression of collagen IV, fibronectin and α-SMA in the HBECs, and its mechanism may be related to the inhibition of NF-κB/TGF-β1/Smad3 pathway.     

Hypoxia-inducible factor-1α attenuates myocardial inflammatory injury induced by ischemia and reperfusion in rats

AIM:To investigate the role of hypoxia-inducible factor-1α (HIF-1α) stable expression in myocardial inflammatory injury induced by ischemia and reperfusion (I/R) in rats. METHODS:Male Wistar rats were randomly divided into 4 groups:sham operation (sham) group, I/R group, HIF-1α stabilizer dimethyloxalyl glycine (DMOG)+I/R group and HIF-1α inhibitor YC-1+I/R group. The protein expression of myocardial Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) was determined by Western blot. The mRNA levels of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, TLR4 and NF-κB were detected by real-time PCR. The myeloperoxidase (MPO) activity in the myocardial tissues was measured. HE staining was used to observe the infiltration of inflammatory cells. RESULTS:HIF-1α decreased the infiltration of inflammatory cells, the MPO activity, and the mRNA levels of inflammatory factors IL-1β, IL-6 and TNF-α in the myocardial tissues. HIF-1α also reduced the expression of TLR4 and NF-κB at mRNA and protein levels (P<0.05). CONCLUSION:The stable expression of HIF-1α has an anti-inflammatory effect on the myocardial tissues after I/R injury in rats. The mechanism may be related to the inhibition of TLR4/NF-κB signaling pathway.     

Inhibitory effect of proanthocyanidins B1 and B2 on inflammation of BV-2 cells induced by lipopolysaccharide

AIM: To investigate the different inhibitory effects of proanthocyanidins B1 and B2, which are isomers, on the inflammatory response of BV-2 cells induced by lipopolysaccharide (LPS). METHODS: MTT assay was used to detect the effects of proanthocyanidins B1 and B2 on the viability of BV-2 cells. LPS (1 mg/L) was used to promote BV-2 cells to secrete inflammatory factors. ELISA, chemotaxis assay and Western blot were used to detect the influence of proanthocyanidins B1 and B2 on the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), cell chemotaxis and phosphorylation of NF-κB. RESULTS: Proanthocyanidins B1 and B2 did not show cytotoxicity effect on BV-2 cells. Proanthocyanidin B1 and B2 inhibited the cell chemotaxis, phosphorylation of NF-κB, and releases of TNF-α and IL-1β. CONCLUSION: Proanthocyanidins B1 and B2 inhibit the inflammatory response of BV-2 cells induced by LPS, and their action intensity didn't show significant difference.     

Knock-down of TLR4 expression reduces secretion of inflammatory factors in LPS-induced pancreatic acinar AR42J cells

AIM:To study the effect of Toll-like receptor 4 (TLR4) on the secretion of inflammatory factors in the pancreatic acinar AR42J cells induced by lipopolysaccharides (LPS). METHODS:The rat pancreatic acinar AR42J cells were treated with LPS. The expression of TLR4 at mRNA and protein levels was determined by real-time PCR and Western blot. The lentivirus carrying TLR4 small interfering RNA (siRNA) was used to infect the AR42J cells. Under LPS stimulation, the interference efficacy was measured by real-time PCR and Western blot. The cell viability was measured by MTT assay, and the leakage rate of lactate dehydrogenase (LDH) was examined by dinitrophenylhydrazine method. The releases of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the cell culture medium were detected by ELISA, and the malondialdehyed (MDA) content in supernatant was measured by thiobarbituric acid method. The activity of superoxide dismutase (SOD) in the supernatant was determined by xanthine oxidation, and the activity of glutathione peroxidase (GSH-Px) and catalase (CAT) was detected by colorimetry. RESULTS:The expression of TLR4 at mRNA and protein levels in LPS-treated AR42J cells was significantly increased (P<0.05). Infection with TLR4 siRNA-carrying lentivirus significantly inhibited the expression of TLR4 at mRNA and protein levels in the AR42J cells under LPS stimulation(P<0.05). The viability of AR42J cells was decreased after LPS treatment. The leakage rate of LDH was increased, the levels of IL-1β and TNF-α secreted by the AR42J cells were increased, the content of MDA was increased in the supernatant, and the activity of SOD, GSH-Px and CAT was reduced (P<0.05). After knock-down of TLR4 expression, the viability of AR42J cells was increased under LPS stimulation, the LDH leakage rate, secreted levels of IL-1β and TNF-α, and the content of MDA in cell culture medium were decreased, and the SOD, GSH-Px and CAT levels were increased (P<0.05). CONCLUSION:LPS induces the expression of TLR4 in the pancreatic acinar AR42J cells. Knock-down of TLR4 expression reduces the secretion of inflammatory factors IL-1β and TNF-α, and attenuates the oxidative damage in pancreatic acinar AR42J cells induced by LPS.     

Effects of tripterygium glycosides combined with dexamethasone on TLRs/NF-κB signaling pathway in EAE rats

AIM: To investigate the role of TLRs/NF-κB pathway in experimental allergic encephalomyelitis (EAE) rats treated with tripterygium glycosides (TG) + dexamethasone (DX). METHODS: Lewis rats were used in the study and divided into control group, EAE model group, therapy 1 group (EAE rats treated with DX) and therapy 2 group (EAE rats treated with DX+TG). The mean clinical score of the rats was determined. The expression of TLR4 and TLR9 at mRNA and protein levels was detected by the methods of real-time quantitative RT-PCR and immunohistochemistry. The protein level of NF-κB p65 was also measured. The levels of TNF-α, IL-1β and IL-6 were assayed by ELISA. RESULTS: The mean clinical scores at 5th, 16th and 20th day were lower in therapy 1 group and therapy 2 group than that in EAE model group. The mean clinical score in therapy 2 group was even lower than that in therapy 1 group. At the 16th day (the peaking period), the mRNA expression of TLR4 and TLR9 in therapy 1 group and therapy 2 group were obviously lower than that in EAE model group. The protein levels of TLR4, TLR9 and NF-κB p65 were also significantly lower in therapy 1 group and therapy 2 group than those in EAE model group at peak stage of EAE. The levels of TNF-α, IL-1β and IL-6 were lower in therapy1 group and therapy2 group than those in EAE model group. The significant differences of the mean clinical score, the mRNA expression of TLR4 and TLR9, the positive ratio of NF-κB p65 and the levels of TNF-α, IL-1β and IL-6 between therapy 1 group and therapy 2 group were found. The result of orthogonal factorial analysis of variance indicated that the difference of therapeutic effect between DX and DX+TG was significant (F=75.749, P<0.01). CONCLUSION: The TLRs/NF-κB pathway takes part in the pathological process of EAE. TG combined with DX alleviates the symptoms of EAE by suppressing inflammatory and immunological reactions of EAE.     

Hydrogen sulfide attenuates urosepsis-induced acute kidney injury by blocking TLR4/MyD88/PI3K signaling pathway

AIM:To explore the effect of hydrogen sulfide (H₂S) on urosepsis-induced acute kidney injury. METHODS:New Zealand white rabbits were randomly divided into control group, sham group, model (sepsis) group, NaHS treatment (NaHS) group, and NaHS combined with TAK-242 (a TLR4 inhibitor) treatment (NaHS+TAK-242) group. After treatment for 72 h, HE staining was used to measure the histopathological changes of rabbit kidney. The levels of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected by automatic biochemical analyzer. The serum levels of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), procalcitonin (PCT), interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by ELISA. The TLR4/MyD88/PI3K signaling pathway-related proteins in the kidney were determined by Western blot. RESULTS:Compared with control group, obvious damage was observed in the kidneys of septic rabbits, but the kidneys were markedly improved by treatment with NaHS. The levels of BUN, SCr, NGAL, KIM-1, PCT, IL-1β, IL-6 and TNF-α in the septic rabbits were higher than those in control group, and decreased significantly in NaHS group and NaHS+TAK-242 group. The protein levels of TLR4, MyD88, p-PI3K and p-Akt in septic rabbit kidneys were higher than those in control group. However, NaHS or NaHS+TAK-242 inhibited the activation of TLR4/MyD88/PI3K signaling pathway in the kidneys of septic rabbits. CONCLUSION:H₂S play a protective effect on the rabbits with urosepsis-induced acute kidney injury by blocking TLR4/MyD88/PI3K signaling pathway to inhibit inflammatory response.     

Hydrogen sulfide inhibits doxorubicin-induced inflammation and cytotoxicity in rat cardiomyocytes by modulating activation of NF-κB pathway

AIM：To investigate whether hydrogen sulfide (H2S) attenuates doxorubicin (DOX)-induced inflammation and cytotoxicity in rat cardiomyocytes (H9c2 cells) by modulating nuclear factor κB (NF-κB) pathway. METHODS：The expression of NF-κB p65 was measured by western blotting. The secretion levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor α (TNF-α) were tested by enzyme-linked immunosorbent assay (ELISA). Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay. Hoechst 33258 nuclear staining was used to detect the morphological changes and number of apoptotic cells. RESULTS：Treatment of H9c2 cells with 5 μmol/L DOX significantly up-regulated the expression level of phosphorylated NF-κB p65 (p-p65), and induced inflammation and cytotoxicity, as evidenced by increases in secretion levels of IL-1β, IL-6 and TNF-α and number of apoptotic cells as well as a decrease in cell viability. Pretreatment of H9c2 cells with 400 μmol/L NaHS (a donor of H2S) for 30 min markedly depressed the up-regulation of p-p65 expression induced by DOX. In addition, NaHS pretreatment also reduced DOX-induced inflammatory response and injury, leading to decreases in IL-1β, IL-6 and TNF-α secretion and number of apoptotic cells as well as an increase in cell viability. Similar to the effect of NaHS, pretreatment with 100 μmol/L pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, also blocked DOX-induced cardiac inflammation and cytotoxicity. Co-administration of IL-1 receptor antagonist (IL-1Ra) and DOX reduced DOX-induced activation of NF-κB and cytotoxicity in H9c2 cells. CONCLUSION：During the DOX-induced cardiomyocyte inflammation, there is positive interaction between NF-κB pathway and IL-1β. H2S may protect cardiomyocytes against DOX-induced inflammatory response and cytotoxicity by inhibiting NF-κB pathway.     

Effect of recombinant rat CC16 protein on LPS-induced expression of TNF-α, IL-6 and IL-8 in rat tracheal epithelial cells

AIM: To explore the effect of recombinamt rat CC16 protein (rCC16) on LPS-induced expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and IL-8 in the rat tracheal epithelial (RTE) cells.METHODS: The RTE cells were incubated with rCC16 at concentrations of 0.5, 1.0 and 2.0 mg/L in serum-free media for 2 h prior to LPS (0.1 mg/L) treatment for further 24 h. The cells were harvested for assessing the mRNA levels of TNF-α, IL-6 and IL-8 by RT-qPCR. The cell culture supernatants were collected for analyzing the protein levels of TNF-α, IL-6 and IL-8 by ELISA. In addition, the nuclear translocation of nuclear factor-κB (NF-κB) p65 was tested by Western blot.RESULTS: rCC16 inhibited LPS-induced IL-6 and IL-8 expression at both mRNA and protein levels in the RTE cells in a concentration-dependent (0~2 mg/L) manner, as demonstrated by RT-qPCR and ELISA. However, no concentration-dependent manner between the dose of rCC16 and TNF-α expression was observed, and rCC16 inhibited LPS-induced TNF-α expression at lower concentration (0.5 mg/L). rCC16 concentration-dependently inhibited the effects of LPS on the level of nuclear translocation of NF-κB p65.CONCLUSION: rCC16 suppresses LPS-mediated TNF-α, IL-6 and IL-8 production through inactivation of NF-κB activity in RTE cells.[KEY WORDS] CC16 protein; Airway inflammation; LPS; Inflammatory mediators; Nuclear factor-κB     

Effects of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages

AIM: To study the effect of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages. METHODS: Mouse macrophage cell line J774.1 cells were cultured with LPS and liposome-mediated oligodeoxynucleotides, and the levels of TNF-α and IL-6 measured in the different culture supernatant by enzyme linked immunosorbent assay. RNA was extracted from macrophages, and the mRNA expression of TNF-α and IL-6 in macrophages was observed by RT-PCR. RESULTS: NF-κB "decoy" oligodeoxynucleotides decreased the expression of TNF-α and IL-6 in LPS-induced macrophages and inhibited generation of TNF-α and IL-6. The level of TNF-α and IL-6 did not change in control group. CONCLUSIONS: NF-κB "decoy" oligodeoxynucleotides inhibit the expression of TNF-α and IL-6 in LPS-induced macrophages, which is probably due to the specific inhibition of activated NF-κB binding sites .     

Everolimus prevents experimental IgA nephropathy in rats

AIM: To investigate the effects of everolimus on the experimental IgA nephropathy in rats and its possible mechanisms.METHODS: The rat model of experimental IgA nephropathy was established. The rats were randomly divided into control group, IgA group and everolimus treatment group. After the corresponding treatments were given, urinary red blood cells, protein and N-acetyl-β-D-glucosaminidase (NAG) were examined. Immunofluorescence staining was used to analyze the level of IgA precipitation in the renal tissues. Additionally, the protein expression of myeloid differentiation factor 88 (MyD88), TLR4, NF-κB, IL-4 and IL-13 was determined by Western blot. The mRNA levels of IL-4 and IL-13 were detected by qPCR.RESULTS: Everolimus significantly inhibited the increases in the urinary levels of red blood cells, protein and NAG in experimental IgA nephropathy rats. Furthermore, IgA nephropathy-induced increases in the protein expression of MyD88, TLR4, NF-κB, IL-4 and IL-13 were attenuated after everolimus treatment. Similar results were obtained in the mRNA levels of IL-4 and IL-13 by qPCR detection.CONCLUSION: Everolimus improves the impairments of renal function in experimental IgA nephropathy rats as evidenced by decreasing urinary red blood cells, protein and NAG, which may be related to the inhibition of MyD88, TLR4, NF-κB, IL-4 and IL-13 expression.     

α7nAChR is involved in anti-inflammation of physiological concentrations of glucocorticoids

AIM: To explore the role of α7 nicotinic acetylcholine receptor (α7nAChR) in anti-inflammation of glucocorticoids (GCs) at physiological concentrations. METHODS: MTT assay was used to measure the viability of BV-2 cells, which were processed by hydrocortisone at different concentrations. On the basis of inflammatory model induced by LPS in BV-2 cells, experimental groups were divided as follows: (1) control; (2) LPS; (3) GCs＋LPS; (4) methyllycaconitine (MLA)＋GCs＋LPS. The levels of TNF-α and IL-1β in the cell supernatants were detected by ELISA. RESULTS: Hydrocortisone at concentrations of 2 000 and 1 000 nmol/L decreased the cell viability to (76.9±5.5)% and (90.8±7.3)%, respectively, indicating the cellular injury by GCs at over-physiological doses. LPS significantly induced the releases of TNF-α and IL-1β in a time- and dose-dependent manner in BV-2 cells. Hydrocortisone at physiological concentrations (500 and 250 nmol/L) reduced the releases of TNF-α and IL-1β in BV-2 cells stimulated by LPS, and MLA at concentration of 10 nmol/L antagonized the anti-inflammatory effect of GCs. CONCLUSION: α7nAChR is involved in the anti-inflammatory effect of the physiological concentrations of GCs.     

Role of NOX1 in TNF-α-induced oxidative damage and inflammation in alveolar epithelial cells

AIM: To explore the role of NADPH oxidase 1 (NOX1) in tumor necrosis factor-α (TNF-α)-induced oxidative damage and inflammation in alveolar epithelial cells.METHODS: The mRNA and protein expression levels of NOX1 in alveolar epithelial cells after TNF-α treatment were determined by real-time PCR and Western blot. NOX1 siRNA and its negative control were transfected into the alveolar epithelial cells. After the induction of TNF-α, NOX1 levels in the cells were measured by real-time PCR and Western blot, and the content of malondialdehyde (MDA) in the cells was detected by thiobarbituric acid method. Xanthine oxidation assay was used to detect the activity of superoxide dismutase (SOD) in the cells. The contents of interleukin-4 (IL-4), IL-6 and IL-1β in cell culture medium were examined by ELISA. The rate of apoptosis was analyzed by flow cytometry. Western blot was used to detect the level of apoptotic protein cleaved caspase-3.RESULTS: The expression of NOX1 at mRNA and protein levels in TNF-α-induced cells was increased after induction (P<0.05). After transfection of NOX1 siRNA, the expression of NOX1 at mRNA and protein levels in the cell was downregulated (P<0.05). Transfection of siRNA negative control had no effect on the expression level of NOX1 in the cells. The content of MDA in the cells after TNF-α treatment was increased, the activity of SOD was reduced, the releases of IL-4, IL-6 and IL-1β by the cells were increased, and the apoptotic rate and the level of apoptotic protein cleaved caspase-3 were increased as compared with the cells that were not treated with TNF-α (P<0.05). The content of MDA in the cells with NOX1 knockdown induced by TNF-α was reduced, the activity of SOD elevated, and the releases IL-4, IL-6 and IL-1β, the apoptotic rate and the level of apoptotic protein cleaved caspase-3 decreased, as compared with the cells only treated with TNF-α induction (P<0.05).CONCLUSION: TNF-α induces the expression of NOX1 in the alveolar epithelial cells. Knockdown of NOX1 expression reduces cellular oxidative damage, releases of inflammatory factors, and cell apoptosis.     

Opening of ATP-sensitive K+ channels protects H9c2 cardiac cells against high glucose-induced injury and inflammation by inhibiting TLR4/NF-κB pathway

AIM: To investigate whether the opening of ATP-sensitive K⁺(K_ATP) channels protects H9c2 cardiac cells against high glucose(HG)-induced injury and inflammation by inhibiting the Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) pathway. METHODS: The protein levels of TLR4 and NF-κB p65 were determined by Western blot. The levels of interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) were detected by ELISA. The cell viability was measured by CCK-8 assay. Mitochondrial membrane potential(MMP) was examined by rhodamine 123(Rh 123) staining followed by photofluorography. The intracellular levels of reactive oxygen species(ROS) were detected by 2', 7'-dichlorfluorescein- diacetate(DCFH-DA) staining followed by photofluorography. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining followed by photofluorography. RESULTS: After the H9c2 cardiac cells were treated with HG(35 mmol/L glucose) for 24 h, the protein levels of TLR4 and phosphorylated NF-κB p65(p-NF-κB p65) were significantly increased. Pretreatment of the cells with 100 μmol/L diazoxide(DZ, a K_ATP channel opener) for 30 min before exposure to HG considerably blocked the up-regulation of the TLR4 and p-NF-κB protein levels induced by HG. Moreover, co-treatment of the cells with 30 μmol/L TAK-242(an inhibitor of TLR4) obviously inhibited the HG-induced up-regulation of the p-NF-κB p65 protein level. On the other hand, pretreatment of the cells with 100 μmol/L DZ had a clear myocardial protection effect, which attenuated the HG-induced cytotoxicity, inflammatory response, mitochondrial damage, oxidative stress and apoptosis, evidenced by an increase in the cell viability, and decreases in the levels of IL-1β and TNF-α, MMP loss, ROS generation and the number of apoptotic cells. Similarly, co-treatment of H9c2 cardiac cells with 30 μmol/L TAK-242 or 100 μmol/L PDTC(an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries and inflammation induced by HG.CONCLUSION: The opening of K_ATP channels protects H9c2 cardiac cells against HG-induced injury and inflammation by inhibiting the TLR4/NF-κB pathway.     

Curcumin reduces neuroinflammation stimulated by Aβ25-35 in primary rat microglial cells

AIM: To investigate the effects of curcumin (Cur) on the expression of High mobility group box 1 protein (HMGB1), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) in amyloid-β (Aβ)-induced primary rat microglial cells. METHODS: Microglia were derived from the cerebral cortices of postnatal rat brains. The cells were identified by immunocytochemistry using mouse anti rat Iba-1 monoclonal antibody. A cell model using primary rat microglial cells incubated with Aβ_25-35 as an inflammation model of Alzheimer's disease (AD) was set up. The morphological characters of primary rat microglial cells were observed. The concentration of Aβ_25-35 and the treatment concentration of curcumin were selected by CCK-8 assay. Cultured primary rat microglial cells were divided into 5 groups:normal cell group, Aβ_25-35 group, Cur group, Aβ_25-35+Cur group and Aβ_25-35+DMSO group. The expression of HMGB1, NF-κB, and receptor for advanced glycation end products (RAGE) was detected by Western blot. The levels of HMGB1, IL-1β, and TNF-α in the culture supernatant were measured by ELISA. RESULTS: The purity of primary microglias determined by Iba-1 immunofluorescence was more than 95%. The protein levels of HMGB1, RAGE and NF-κB were significantly increased after Aβ_25-35 stimulation. After treatment with Cur, the protein levels of HMGB1, RAGE and NF-κB were significantly decreased (P<0.05). The levels of HMGB1, IL-1β and TNF-α in the supernatant were significantly increased after Aβ_25-35 stimulation. Cur significantly decreased the level of HMGB1, IL-1β and TNF-α in the supernatant. CONCLUSION: Curcumin significantly inhibits neuroinflammation stimulated by Aβ_25-35 in primary rat microglial cells.     

Effect of TRPV1 activation on lipopolysaccharide-induced lung inflammatory injury in mice

AIM:To investigate the effects of transient receptor potential cation channel subfamily V member 1 (TRPV1) activation by capsaicin on the inflammation and its underlying mechanisms in lipopolysaccharide (LPS)-induced lung injury in mice. METHODS:A total of 108 specific pathogen-free male ICR mice were randomly divided into 6 groups: normal control group, capsaicin (CAP) control group, capsazepine (CAPZ) control group, endotoxemia group, CAP treatment group and CAPZ treatment group. LPS was intraperitoneally injected 30 min after the subcutaneous injection of CAP or CAPZ. After modeling, the levels of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), IL-10, substance P (SP) and calcitonin gene-related peptide (CGRP) in the lung were measured by ELISA. The expression of Toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) in the lung tissue was assessed by Western blotting. The pathological changes of the lung tissue were observed under light microscope. RESULTS:The expression of TNF-α, IL-6, IL-10 and NF-κB in the lung tissues at 3 h, 8 h and 16 h was dramatically higher in endotoxemia group than that in normal control group. Compared with endotoxemia group, the levels of TNF-α, IL-6 and nuclear NF-κB in CAP treatment group at 3 h, 8 h and 16 h were obviously decreased, but the level of IL-10 was increased. The changes of the factors mentioned above in CAPZ treatment group were absolutely adverse to those in CAP treatment group. The levels of SP and CGRP were significantly higher in endotoxemia group and CAP control group than those in normal control group, but those in CAPZ control group were lower. Compared with endotoxemia group, SP and CGRP were markedly increased in CAP treatment group and were obviously decreased in CAPZ treatment group. The level of TLR4 in endotoxemia group was distinctly higher than that in normal control group at 3 h, 8 h and 16 h. However, as compared with endotoxemia group, the expression of TLR4 in CAP treatment group and CAPZ treatment group didn’t change much. At 8 h and 16 h after modeling, the degree of lung damage was also decreased in CAP treatment group as compared with endotoxemia group, while that in CAPZ treatment group was aggravated. CONCLUSION: TRPV1 activation obviously inhibits the increase in TNF-α, IL-6 and NF-κB in the lung tissue of endotoxemia mice, and promotes the increase in the anti-inflammatory factor IL-10, as well as the levels of SP and CGRP, but has no effect on the expression of TLR4.