IKKβ mediates homeostatic function in inflammation via competitively phosphorylating AMPK and IκBα

Inhibitor of nuclear factor kappa-B kinase subunit beta (IKKβ) is one of important kinases in inflammation to phosphorylate inhibitor of nuclear factor kappa-B (IκBα) and then activate nuclear factor kappa-B (NF-κB). Inhibition of IKKβ has been a therapeutic strategy for inflammatory and autoimmune diseases. Here we report that IKKβ is constitutively activated in healthy donors and healthy Ikkβ C46A (cysteine 46 mutated to alanine) knock-in mice although they possess intensive IKKβ-IκBα-NF-κB signaling activation. These indicate that IKKβ activation probably plays homeostatic role instead of causing inflammation. Compared to Ikkβ WT littermates, lipopolysaccharides (LPS) could induce high mortality rate in Ikkβ C46A mice which is correlated to breaking the homeostasis by intensively activating p-IκBα-NF-κB signaling and inhibiting phosphorylation of 5' adenosine monophosphate-activated protein kinase (p-AMPK) expression. We then demonstrated that IKKβ kinase domain (KD) phosphorylates AMPKα1 via interacting with residues Thr183, Ser184, and Thr388, while IKKβ helix-loop-helix motifs is essential to phosphorylate IκBα according to the previous reports. Kinase assay further demonstrated that IKKβ simultaneously catalyzes phosphorylation of AMPK and IκBα to mediate homeostasis. Accordingly, activation of AMPK rather than inhibition of IKKβ could substantially rescue LPS-induced mortality in Ikkβ C46A mice by rebuilding the homeostasis. We conclude that IKKβ activates AMPK to restrict inflammation and IKKβ mediates homeostatic function in inflammation via competitively phosphorylating AMPK and IκBα.

Effect of Gegen Qinliantang on TLR4/IKKβ/NF-κB Pathway in KKAy Mice with Diabetes / 中国实验方剂学杂志

ObjectiveTo observe the effect of classical prescription Gegen Qinliantang（GGQLT） on inflammatory factors and key targets in the inflammatory pathways mediated by lipopolysaccharide in KKAy mice and explore its mechanism in improving spontaneous type 2 diabetes mellitus （T2DM）. MethodSixty-five SPF KKAy mice with spontaneous T2DM and 13 C57BL/6J mice （control） were selected in the barrier system and fed on a high-fat diet. The model was properly induced in 44 mice in the context of random blood glucose exceeding or equal to 13.9 mmol·L-1. Then the mice were assigned into a normal group （20 mL∙kg-1 normal saline）， a model group （20 mL∙kg-1 normal saline）， an acarbose group （3.9 mg∙kg-1）， and high- and low-dose GGQLT groups （1.82 and 0.45 g∙kg-1）， with 11 mice in each group. The mice in each group were treated correspondingly by gavage for eight weeks， once per day. Blood glucose and body weight were systematically evaluated. Twelve hours after the last administration， blood samples were collected from the eyes， and the serum and muscle and liver tissues were extracted. The levels of tumor necrosis factor-α （TNF-α）， interleukin-6 （IL-6）， and glucose transporter type 4 （GluT4） were detected by semi-quantitative enzyme-linked immunosorbent assay （ELISA）. The protein expression of IκB kinase β （IKKβ） and nuclear factor-κB （NF-κB） in muscle tissues and Toll-like receptor 4 （TLR4） in liver tissues was detected by Western blot. ResultCompared with the normal group， the model group showed increased body weight and blood glucose （P<0.01）. Compared with the model group， the acarbose group and the GGQLT groups showed reduced body weight and blood glucose （P<0.05， P<0.01）. As revealed by ELISA results， compared with the normal group， the model group showed increased levels of TNF-α and IL-6 （P<0.01） and deceased GluT4 level （P<0.05）. Compared with the model group， the groups with drug treatment showed reduced levels of TNF-α and IL-6 （P<0.05， P<0.01）， and the acarbose group and the high-dose GGQLT group showed increased GluT4 level （P<0.05， P<0.01）. As displayed by Western blot results， compared with the normal group， the model group showed increased protein expression of IKKβ， NF-κB， and TLR4 （P<0.01）. Compared with the model group， the acarbose group and the GGQLT groups showed reduced protein expression of IKKβ， NF-κB， and TLR4 （P<0.05， P<0.01）. ConclusionGGQLT can inhibit the inflammatory cascade effect and improve T2DM by down-regulating the levels of key inflammatory factors in the TLR4 pathway， inhibiting their activation， and increasing the translocation and activity of GluT4 on the basis of the regulation of intestinal flora.

Effect of Weiwei Tongtiao Decoction on Expression of IKKβ, Bcl-2 in CAG Precancerous Lesion Rats / 中国实验方剂学杂志

Objective:To investigate the effect of Weiwei Tongtiao decoction on gastric mucosal pathology and the expression level of inhibitor kappa B kinase <italic>β</italic>（IKK<italic>β</italic>） and B-cell lymphoma-2（Bcl-2）in rats with chronic atrophic gastritis （CAG） precancerous lesion. Method:SD rats were randomly divided into normal group， model group， positive drug Weifuchun group， Weiwei Tongtiao decoction high， medium and low dose treatment groups. The rat model of CAG precancerous lesion was prepared by <italic>N</italic>-methyl-<italic>N</italic>'-nitro-<italic>N</italic>-nitrosoguanidine （MNNG）compound modeling method. weiwei Tongtiao decoction high， medium and low dose treatment groups received intragastric administration of 24， 12， 6 g·kg^-1 Weiwei Tongtiao decoction respectively， while Weifuchun group received 0.45 g·kg^-1 Weifuchun suspension， once per day for 12 weeks. The pathological changes of gastric mucosa of rats were observed by hematoxylin-eosin（HE）staining， and the mRNA and protein levels of IKK<italic>β</italic> and Bcl-2 in gastric mucosa of rats were detected by Real-time quantitative polymerase chain reaction （Real-time PCR）， immunohistochemistry（IHC）and Western blot. Result:Compared with the normal group， 100% inherent gland atrophy， mild to severe intestinal metaplasia， and 25% low-grade intraepithelial neoplasia were observed under microscope in model group. All Weifuchun group and Weiwei Tongtiao decoction groups could improve the atrophy of gastric glands， moderate to severe intestinal metaplasia and pathological injury of low-grade intraepithelial neoplasia， especially at high dose group. Compared with the normal group， IKK<italic>β</italic>， Bcl-2 mRNA and protein expressions in the gastric mucosa of the model group were up-regulated （<italic>P</italic><0.01）. Compared with the model group， the mRNA and protein expressions of IKK<italic>β</italic> and Bcl-2 in gastric mucosa of rats in the Weifuchun group and the Weiwei Tongtiao decoction high， medium and low dose groups were down-regulated （<italic>P</italic><0.05，<italic>P</italic><0.01）， showing a dose-dependent relationship， and such levels in the Weiwei Tongtiao decoction high-dose intervention group were similar to those in normal group. Conclusion:Weiwei Tongtiao decoction can improve and even reverse gastric mucosa with CAG precancerous lesions in rats， and its intervention mechanism may be related to down-regulating the expressions of IKK<italic>β</italic> and Bcl-2 in gastric mucosa.

Apoptotic and cytostatic actions of maslinic acid in colorectal cancer cells through possible IKK-β inhibition

Objective: To explore the anti-cancer activity of maslinic acid against colorectal cancer (CRC) cell lines and its possible mechanism. Methods: The inhibitory effect of maslinic acid was screened against five CRC cell lines (HT-29, HCT 116, SW480, SW48, and LS 174T) via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis and cell cycle analyses were carried out using annexin Ⅴ-FITC/propidium iodide staining and propidium iodide staining, respectively and subjected to fluorescence-activated cell sorting analysis. Protein expression studies of inhibitor of κB kinase-β (IKK-β), checkpoint kinase 1 (Chk1) and cyclin D1 were conducted using the JESS system. Results: Maslinic acid exhibited growth inhibitory effect in a dose- and time-dependent manner in HT-29 and HCT 116 cell lines. A more prominent apoptosis induced by maslinic acid was observed in HCT 116 cell line. However, in HT-29 cell line, maslinic acid induced cell cycle arrest by inhibiting the G1-S transition, which was accompanied by the downregulation of cyclin D1. The expression of unphosphorylated IKK-β protein was increased in both (HT-29 and HCT 116) cell lines after maslinic acid treatment. Conclusions: Maslinic acid inhibits the growth of HT-29 and HCT 116 cells in a different manner, induces cell cycle arrest in HT-29 cells and causes apoptosis in HCT 116 cells partially via NF-κB pathway inhibition.

Apoptotic and cytostatic actions of maslinic acid in colorectal cancer cells through possible IKK-β inhibition

Objective: To explore the anti-cancer activity of maslinic acid against colorectal cancer (CRC) cell lines and its possible mechanism. Methods: The inhibitory effect of maslinic acid was screened against five CRC cell lines (HT-29, HCT 116, SW480, SW48, and LS 174T) via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis and cell cycle analyses were carried out using annexin V-FITC/propidium iodide staining and propidium iodide staining, respectively and subjected to fluorescence-activated cell sorting analysis. Protein expression studies of inhibitor of κB kinase-β (IKK-β), checkpoint kinase 1 (Chk1) and cyclin D1 were conducted using the JESS system. Results: Maslinic acid exhibited growth inhibitory effect in a doseand time-dependent manner in HT-29 and HCT 116 cell lines. A more prominent apoptosis induced by maslinic acid was observed in HCT 116 cell line. However, in HT-29 cell line, maslinic acid induced cell cycle arrest by inhibiting the G1-S transition, which was accompanied by the downregulation of cyclin D1. The expression of unphosphorylated IKK-β protein was increased in both (HT-29 and HCT 116) cell lines after maslinic acid treatment. Conclusions: Maslinic acid inhibits the growth of HT-29 and HCT 116 cells in a different manner, induces cell cycle arrest in HT-29 cells and causes apoptosis in HCT 116 cells partially via NF-κB pathway inhibition.

Loss of IκB kinase β promotes myofibroblast transformation and senescence through activation of the ROS-TGFβ autocrine loop

Using forward and reverse genetics and global gene expression analyses, we explored the crosstalk between the IκB kinase β (IKKβ) and the transforming growth factor β (TGFβ) signaling pathways. We show that in vitro ablation of Ikkβ in fibroblasts led to progressive ROS accumulation and TGFβ activation, and ultimately accelerated cell migration, fibroblast-myofibroblast transformation and senescence. Mechanistically, the basal IKKβ activity was required for anti-oxidant gene expression and redox homeostasis. Lacking this activity, IKKβ-null cells showed ROS accumulation and activation of stress-sensitive transcription factor AP-1/c-Jun. AP-1/c-Jun activation led to up-regulation of the Tgfβ2 promoter, which in turn further potentiated intracellular ROS through the induction of NADPH oxidase (NOX). These data suggest that by blocking the autocrine amplification of a ROS-TGFβ loop IKKβ plays a crucial role in the prevention of fibroblast-myofibroblast transformation and senescence.

NIBP regulates colon cancer cell express MMP2 and MMP9 via NF-κB signaling pathways / 实用医学杂志

Objective To observe after the NIBP (NIK and IKK beta binding protein) gene transfected into colon cancer cell lines HT29, the migration of cells and expression of p65, MMP2, MMP9 mRNA and proteins. Methods The experimental group: divided into without transfection HT29 cell (HT29 group) and transfection no-load HT29 cell (HT29-NC group) and transfection NIBP HT29 cell (HT29-NIBP steady group). Using the Transwell test to detect cell migration ability. Q-PCR method to detect the mRNA expressions of NIBP , p65, MMP2, MMP9. Western Blot method to detect the expressions of NIBP, p65, phosphorylation p65 (p-p65) proteins. The method of ELISA was used to detect the secretion of matrix metalloproteinase (MMP)-2, MMP-9. Results The high expression of NIBP may enhance the migration ability of colon cancer cell lines HT29 , increasing the expression of p-p65, MMP2, MMP9 mRNA and proteins (P < 0.05). Conclusion NIBP potently enhances colon cancer HT29 cell migration and invasion. Activation of NF-κB signaling pathways resulted in up-regulation of MMP-2 and MMP-9 maybe one of its molecular mechanisms.

BMS-345541 regulates repair of DNA double-strand breaks induced by VP-16 in acute myeloid leukemia cells / 中国药理学通报

Aim To investigate the effect of BMS- 345541 on the repair of DNA DSBs induced by VP-16 in AML cells and its possible mechanism. Methods The effects of BMS-345541 on the sensitivity of AML cells to VP-16 were determined by MTT. Flow cytome-try ( FCM) was applied to test the level of DNA dam-age, cell cycle progression and apoptosis in AML cells. High content analysis ( HCA) was used to verify the amount ofγ-H2AX,p-ATM,RAD51 in AML cells. Results BMS-345541 could significantly inhibit the proliferation of AML cells induced by VP-16 . BMS- ＜br> 345541 increased the amount of RAD51 foci and p-ATM foci in AML cells treated with VP-16 after 6 hours , which led to increased numbers of cells in the G2/M phases of the cell cycle,then induced apoptotic cell death. Conclusion BMS-345541 sensitizes AML cells to VP-16 via selective inhibition of homologous recombinational repair of DNA double-strand breaks.

Migration and proliferation of human mesenchymai stem cells from patients with systemic lupus erythematosus mediated by IKK-β / 中华风湿病学杂志

ObjectiveTo investigate the effect of IκB kinase (IKK-β) on migration and proliferation of bone marrow mesenchymal stem cells(BMSCs) from patients with systemic lupus erythematosus (SLE).MethodsHuman bone marrow aspirates were collected from iliac of six donors and six SLE patients and cultured in vitro.Migration of BMSCs were observed by wound healing and transwell migration assays.Proliferation of BMSCs was quantified by cell counting kit-8 assay.Total RNA was extracted and reverse transcribed into complementary DNA.Real-time PCR technique was used to determine the gene expression of IKK-β at transcription level.The expression of IKK-β and phospho-IKK-β(p-IKK-β) protein were determined by Western blotting analysis.Statistical analysis was conducted with or Mann-Whitney rank test.Results① The migration rate of BMSCs from SLE patients(5.2±3.8)‰ were significantly reduced as compared with normal controls (7.0±2.9)‰(P＜0.05 ).The proliferation of BMSCs of SLE patients (0.21±0.49)was lower than that from healthy controls ( 1.00±0.35 )(P＜0.05 ).②) No difference in IKK-β3 mRNA expression between SLE ( 1.9± 1.4) subjects and normal controls (1.9±2.4) (P＞0.05).IKK-β protein expression of BMSCs from SLE patients (1.41 ±0.19) increased significantly compared with healthy controls (0.93±1.24) (P＜0.05).③ Inhibitor of IKK-β caused a significant increase in cell migration (3.3±1.6)‰ and proliferation (1.13±0.26) of BMSCs from SLE patients compared with untreated cells (2.3±1.1)‰ and (0.81±0.17),respectively (P＜0.05).ConclusionMigration and proliferation of BMSCs are significantly decreased in SLE patients.IKK-β may be involved in migration and proliferation of BMSCs.

The effect of smoking and smoking cessation on the phosphorylation of IKK-β in type 2 diabetic rats / 中华内科杂志

Objective To investigate the effect of smoking and smoking cessation on the phosphorylation of IKK-β in type 2 diabetic rats. Methods Forty-two six-week-old Wistar rats were randomly divided into 4 groups: normal control(NC, n =7), diabetes control (DC, n =7), diabetes with smoking (DS, n = 14) and diabetes with smoking cessation(SC, n = 14). Rats in DS and SC groups were further assigned randomly into 8w and 12w subgroups. DS group was given passive smoking twice a day for 8 or 12 weeks, while SC group ceased passive smoking for 4 weeks after 8 or 12 weeks of smoking . Western blot method was used to detect the level of IKK-13 phosphorylation in skeletal muscle. Results Compared with the NC group,the phosphorylation of IKK-β protein in DC group was increased (0. 16±0. 05 vs 0. 30±0. 08, P < 0. 01). There was an increasing trend with the phosphorylation level of IKK-β in the DS (8w) subgroup, but there was no statistical difference between the DC group and SC(8w) subgroup (0. 40±0. 09 vs 0. 30±0. 08,0. 36±0. 10, P >0. 05). The phosphorylation level of IKK-β in DS(12w) group increased obviously, being significantly higher than that in the DC group and SC (12w) subgroup(0. 74 ± 0. 11 vs 0.30±0.08,0.35±0.07,P < 0.01). Conclusion With the prolongation of smoking duration, the phosphorylation of IKK-β in type 2 diabetic rats increased. After smoking cessation, the phosphorylation of IKK-β decreased. The phosphorylation of IKK-β may be involved in the mechanism by which smoking causes type 2 diabetes.

α-lipoic acid inhibits the effects of Iκβ kinase β on islet / 中华内分泌代谢杂志

Objective To investigate the effects of differentiated 3T3-L1 adipoeytes on inflammation of rat islet cells,as well as the protective effect of a-lipoic acid on the inflammation in vitro.Methotis Rat islet cells were divided into three groups:the control group,the experimental co-culture system group(cocuhured with differentiated mature 3T3-LI adipoeytes)and the intervention group (cocuhured with mature 3T3-LI adipocytes containing 4 μg/ml a-lipoic acid).Insulin releasing lest wag performed for estinmting the function of islet cells in culture supernatant of difierent groups.At the same time,the expression level of IKKIβin islet cells Was detected by western blot and realtime PCR.Results There was significant decrease of insulin stimulation index (SI) in experimental co-culture system group compared with the control group and intervention group(1.0 ±0.1 vs 2.6±0.2,2.5±0.5 respectively;P<0.01),while,the mRNA(4.62±0.60 vs1.00±0.46 and 2.25±0.75;P<0.01)and protein expression of IKKβ were significandy increased in the experimental group as compared with the other two groups.Conclusions In the co-culture system of adipocytes/islet cells,impaired function of islet cells could be induced by IKKβ activation,IKKβ Was a key molecule in inflamnmtion signal pathway in islet cells and could be activated by 3T3-LI adipocytes.a-lipoic acid Was able to reverse the impaired function of islet cells by suppressing IKKβ expression.