scholarly journals Crucial roles of binding sites for NF-κB and C/EBPs in IκB-ζ-mediated transcriptional activation

2007 ◽  
Vol 405 (3) ◽  
pp. 605-615 ◽  
Author(s):  
Susumu Matsuo ◽  
Soh Yamazaki ◽  
Koichiro Takeshige ◽  
Tatsushi Muta

IκB-ζ [inhibitor of NF-κB (nuclear factor κB) ζ] is a nuclear protein that is induced upon stimulation of TLRs (Toll-like receptors) and IL (interleukin)-1 receptor. IκB-ζ harbours C-terminal ankyrin repeats that interact with NF-κB. Our recent studies have shown that, upon stimulation, IκB-ζ is essential for the induction of a subset of inflammatory genes, represented by IL-6, whereas it inhibits the expression of TNF (tumour necrosis factor)-α. In the present study, we investigated mechanisms that determine the different functions of IκB-ζ. We found that co-expression of IκB-ζ and the NF-κB subunits synergistically activates transcription of the hBD-2 (human β-defensin 2) and NGAL (neutrophil gelatinase-associated lipocalin) genes, whereas it inhibits transcription of E-selectin. Reporter analyses indicated that, in addition to an NF-κB-binding site, a flanking C/EBP (CCAAT/enhancer-binding protein)-binding site in the promoters is essential for the IκB-ζ-mediated transcriptional activation. Using an artificial promoter consisting of the NF-κB- and C/EBP-binding sites, transcriptional activation was observed upon co-transfection with IκB-ζ and NF-κB, indicating that these sequences are minimal elements that confer the IκB-ζ-mediated transcriptional activation. Chromatin immunoprecipitation assays and knockdown experiments showed that both IκB-ζ and the NF-κB subunits were recruited to the NGAL promoter and were essential for the transcriptional activation of the hBD-2 and NGAL promoters on stimulation with IL-1β. The activation of the NGAL promoter by transfection of IκB-ζ and NF-κB was suppressed in C/EBPβ-depleted cells. Thus IκB-ζ acts as an essential transcriptional activator by forming a complex with NF-κB on promoters harbouring the NF-κB- and C/EBP-binding sites, upon stimulation of TLRs or IL-1 receptor.

2009 ◽  
Vol 424 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Hosea Handoyo ◽  
Margaret J. Stafford ◽  
Eamon McManus ◽  
Dionissios Baltzis ◽  
Mark Peggie ◽  
...  

The protein kinase Tpl2 (tumour progression locus 2) is activated by LPS (lipopolysaccharide), TNFα (tumour necrosis factor α) and IL (interleukin)-1. Activation of the native Tpl2 complex by these agonists requires the IKKβ {IκB [inhibitor of NF-κB (nuclear factor κB)] kinase β}-catalysed phosphorylation of the p105/NF-κB1 subunit and is accompanied by the release of the catalytic subunit from both p105/NF-κB1 and another subunit ABIN2 (A20-binding inhibitor of NF-κB 2). In the present study we report that IL-1 activates the transfected Tpl2 catalytic subunit in an HEK (human embryonic kidney)-293 cell line that stably expresses the IL-1R (IL-1 receptor), but does not express the protein kinase IRAK1 (IL-1R-associated kinase). In these cells IL-1 does not activate IKKβ or induce the phosphorylation of p105/NF-κB1, and nor does the IKKβ inhibitor PS1145 prevent the IL-1-induced activation of transfected Tpl2. However, the IL-1-stimulated activation of transfected Tpl2 in IRAK1-null cells or activation of the endogenous Tpl2 complex in IRAK1-expressing cells is suppressed by the protein kinase inhibitor PP2 by a mechanism that does not involve inhibition of Src family protein tyrosine kinases. The IL-1-stimulated activation of transfected Tpl2 is accompanied by its phosphorylation at Thr290 and Ser400 and by enhanced phosphorylation of Ser62, which we demonstrate are autophosphorylation events catalysed by Tpl2 itself. We further show that IL-1 triggers the dissociation of Tpl2 from co-transfected ABIN2 in IRAK1-null IL-1R cells, which is not suppressed by PP2 or by the inhibition of Tpl2 or IKKβ. These studies identify two new signalling events involved in activation of the native Tpl2 complex by IL-1. First, the IRAK1-, IKKβ- and PP2-independent dissociation of Tpl2 from ABIN2; secondly, the IRAK1- and IKKβ-independent, but PP2-sensitive, activation of the Tpl2 catalytic subunit.


2017 ◽  
Vol 37 (9) ◽  
pp. 937-943 ◽  
Author(s):  
AA Fouad ◽  
WN Al-Melhim

The present study investigated the probable protective effect of vanillin (VLN) against kidney injury induced by cisplatin (CSN) and methotrexate (MTX) in rats. The rats received a single injection of either CSN (7.5 mg/kg, i.p.) or MTX (20 mg/kg, i.p.). VLN treatment (150 mg/kg/day, i.p.) was started 1 day before administration of the nephrotoxic agents and continued for 7 days. Both CSN and MTX significantly increased serum creatinine, cystatin C, and neutrophil gelatinase–associated lipocalin and kidney tissue renal malondialdehyde, inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-18, nuclear factor-κB p65, cytosolic cytochrome C, and caspase-3 and significantly decreased renal total antioxidant capacity and Bcl-2/Bax ratio in rats. VLN significantly ameliorated the changes of biochemical parameters induced by CSN and MTX. VLN also significantly reduced CSN- and MTX-induced histopathological injury and the expression of Fas ligand in rat kidneys. In conclusion, VLN significantly protected against CSN- and MTX-induced kidney injury in rats by inhibiting oxidative/nitrosative stress, inflammation, and apoptosis.


1994 ◽  
Vol 14 (9) ◽  
pp. 5986-5996
Author(s):  
S P Hunger ◽  
R Brown ◽  
M L Cleary

The t(17;19) translocation in acute lymphoblastic leukemias results in creation of E2A-hepatic leukemia factor (HLF) chimeric proteins that contain the DNA-binding and protein dimerization domains of the basic leucine zipper (bZIP) protein HLF fused to a portion of E2A proteins with transcriptional activation properties. An in vitro binding site selection procedure was used to determine DNA sequences preferentially bound by wild-type HLF and chimeric E2A-HLF proteins isolated from various t(17;19)-bearing leukemias. All were found to selectively bind the consensus sequence 5'-GTTACGTAAT-3' with high affinity. Wild-type and chimeric HLF proteins also bound closely related sites identified previously for bZIP proteins of both the proline- and acidic amino acid-rich (PAR) and C/EBP subfamilies; however, E2A-HLF proteins were significantly less tolerant of certain deviations from the HLF consensus binding site. These differences were directly attributable to loss of an HLF ancillary DNA-binding domain in all E2A-HLF chimeras and were further exacerbated by a zipper mutation in one isolate. Both wild-type and chimeric HLF proteins displayed transcriptional activator properties in lymphoid and nonlymphoid cells on reporter genes containing HLF or C/EBP consensus binding sites. But on reporter genes with nonoptimal binding sites, their transcriptional properties diverged and E2A-HLF competitively inhibited activation by wild-type PAR proteins. These findings establish a spectrum of binding site-specific transcriptional properties for E2A-HLF which may preferentially activate expression of select subordinate genes as a homodimer and potentially antagonize expression of others through heteromeric interactions.


1992 ◽  
Vol 12 (3) ◽  
pp. 1209-1217
Author(s):  
C F Hardy ◽  
D Balderes ◽  
D Shore

RAP1 is an essential sequence-specific DNA-binding protein in Saccharomyces cerevisiae whose binding sites are found in a large number of promoters, where they function as upstream activation sites, and at the silencer elements of the HMR and HML mating-type loci, where they are important for repression. We have examined the involvement of specific regions of the RAP1 protein in both repression and activation of transcription by studying the properties of a series of hybrid proteins containing RAP1 sequences fused to the DNA-binding domain of the yeast protein GAL4 (amino acids 1 to 147). GAL4 DNA-binding domain/RAP1 hybrids containing only the carboxy-terminal third of the RAP1 protein (which lacks the RAP1 DNA-binding domain) function as transcriptional activators of a reporter gene containing upstream GAL4 binding sites. Expression of some hybrids from the strong ADH1 promoter on multicopy plasmids has a dominant negative effect on silencers, leading to either partial or complete derepression of normally silenced genes. The GAL4/RAP1 hybrids have different effects on wild-type and several mutated but functional silencers. Silencers lacking either an autonomously replicating sequence consensus element or the RAP1 binding site are strongly derepressed, whereas the wild-type silencer or a silencer containing a deletion of the binding site for another silencer-binding protein, ABF1, are only weakly affected by hybrid expression. By examining a series of GAL4 DNA-binding domain/RAP1 hybrids, we have mapped the transcriptional activation and derepression functions to specific parts of the RAP1 carboxy terminus.(ABSTRACT TRUNCATED AT 250 WORDS)


1994 ◽  
Vol 14 (9) ◽  
pp. 5986-5996 ◽  
Author(s):  
S P Hunger ◽  
R Brown ◽  
M L Cleary

The t(17;19) translocation in acute lymphoblastic leukemias results in creation of E2A-hepatic leukemia factor (HLF) chimeric proteins that contain the DNA-binding and protein dimerization domains of the basic leucine zipper (bZIP) protein HLF fused to a portion of E2A proteins with transcriptional activation properties. An in vitro binding site selection procedure was used to determine DNA sequences preferentially bound by wild-type HLF and chimeric E2A-HLF proteins isolated from various t(17;19)-bearing leukemias. All were found to selectively bind the consensus sequence 5'-GTTACGTAAT-3' with high affinity. Wild-type and chimeric HLF proteins also bound closely related sites identified previously for bZIP proteins of both the proline- and acidic amino acid-rich (PAR) and C/EBP subfamilies; however, E2A-HLF proteins were significantly less tolerant of certain deviations from the HLF consensus binding site. These differences were directly attributable to loss of an HLF ancillary DNA-binding domain in all E2A-HLF chimeras and were further exacerbated by a zipper mutation in one isolate. Both wild-type and chimeric HLF proteins displayed transcriptional activator properties in lymphoid and nonlymphoid cells on reporter genes containing HLF or C/EBP consensus binding sites. But on reporter genes with nonoptimal binding sites, their transcriptional properties diverged and E2A-HLF competitively inhibited activation by wild-type PAR proteins. These findings establish a spectrum of binding site-specific transcriptional properties for E2A-HLF which may preferentially activate expression of select subordinate genes as a homodimer and potentially antagonize expression of others through heteromeric interactions.


2020 ◽  
Vol 19 (3) ◽  
pp. 255-260
Author(s):  
Fan Yang ◽  
Lu Deng ◽  
MuHu Chen ◽  
Ying Liu ◽  
Jianpeng Zheng

Acute lung injury initiated systemic inflammation leads to sepsis. Septic mice show a series of degenerative changes in lungs as demonstrated by pulmonary congestion, alveolar collapse, inflammatory cell infiltration, and increased wet-todry weight in lungs. 6-Gingerol ameliorates histopathological changes and clinical outcome of the sepsis. The increase in the levels of tumor necrosis factor-α, interleukin-1 beta, interleukin-6, and interleukin-18 in septic mice were reduced by administration with 6-Gingerol. Also, 6-Gingerol attenuates sepsis-induced increase of malonaldehyde and decrease of catalase, superoxide, and glutathione. Enhanced phospho-p65, reduced nuclear factor erythropoietin-2-related factor 2, and heme oxygenase 1 in septic mice were reversed by administration with 6-Gingerol. In conclusion, 6-Gingerol demonstrates anti-inflammatory and antioxidant effects against sepsis associated acute lung injury through inactivation of nuclear factor-kappa B and activation of nuclear-factor erythroid 2-related factor 2 pathways.


2019 ◽  
Vol 131 (5) ◽  
pp. 1110-1124 ◽  
Author(s):  
Philippe Guerci ◽  
Bulent Ergin ◽  
Aysegul Kapucu ◽  
Matthias P. Hilty ◽  
Ronald Jubin ◽  
...  

Abstract Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Primary resuscitation fluid to treat hemorrhagic shock remains controversial. Use of hydroxyethyl starches raised concerns of acute kidney injury. Polyethylene-glycolated carboxyhemoglobin, which has carbon monoxide–releasing molecules and oxygen-carrying properties, was hypothesized to sustain cortical renal microcirculatory Po2 after hemorrhagic shock and reduce kidney injury. Methods Anesthetized and ventilated rats (n = 42) were subjected to pressure-controlled hemorrhagic shock for 1 h. Renal cortical Po2 was measured in exposed kidneys using a phosphorescence quenching method. Rats were randomly assigned to six groups: polyethylene-glycolated carboxyhemoglobin 320 mg · kg−1, 6% hydroxyethyl starch (130/0.4) in Ringer’s acetate, blood retransfusion, diluted blood retransfusion (~4 g · dl−1), nonresuscitated animals, and time control. Nitric oxide and heme oxygenase 1 levels were determined in plasma. Kidney immunohistochemistry (histologic scores of neutrophil gelatinase-associated lipocalin and tumor necrosis factor-α) and tubular histologic damages analyses were performed. Results Blood and diluted blood restored renal Po2 to 51 ± 5 mmHg (mean difference, −18; 95% CI, −26 to −11; P < 0.0001) and 47 ± 5 mmHg (mean difference, −23; 95% CI, −31 to −15; P < 0.0001), respectively, compared with 29 ± 8 mmHg for hydroxyethyl starch. No differences between polyethylene-glycolated carboxyhemoglobin and hydroxyethyl starch were observed (33 ± 7 mmHg vs. 29 ± 8 mmHg; mean difference, −5; 95% CI, −12 to 3; P = 0.387), but significantly less volume was administered (4.5 [3.3–6.2] vs. 8.5[7.7–11.4] ml; mean rank difference, 11.98; P = 0.387). Blood and diluted blood increased the plasma bioavailability of nitric oxide compared with hydroxyethyl starch (mean rank difference, −20.97; P = 0.004; and −17.13; P = 0.029, respectively). No changes in heme oxygenase 1 levels were observed. Polyethylene-glycolated carboxyhemoglobin limited tubular histologic damages compared with hydroxyethyl starch (mean rank difference, 60.12; P = 0.0012) with reduced neutrophil gelatinase-associated lipocalin (mean rank difference, 84.43; P < 0.0001) and tumor necrosis factor-α (mean rank difference, 49.67; P = 0.026) histologic scores. Conclusions Polyethylene-glycolated carboxyhemoglobin resuscitation did not improve renal Po2 but limited tubular histologic damages and neutrophil gelatinase-associated lipocalin upregulation after hemorrhage compared with hydroxyethyl starch, whereas a lower volume was required to sustain macrocirculation.


1981 ◽  
Vol 241 (4) ◽  
pp. G313-G320
Author(s):  
B. L. Tepperman ◽  
B. D. Soper

Biologically active [3H]prostaglandin E2 (PGE2) bound rapidly and specifically to membrane fractions from hog fundic mucosa. Optimal binding occurred in the 30,000-g membrane preparation at 37 degrees C (pH 5.0). Scatchard analysis of specific PgE2 binding revealed the presence of a heterogeneous population of binding sites with Kd values and binding site concentrations of approximately 1 X 10(-9) M and 1 fmol/mg prot and 2 X 10(-8) M and 20 fmol/mg prot, respectively. Specific binding was inhibited by the following agents in descending order of potency: PGE1, PGA2, PGD2, 6-keto-PGF1 alpha, and thromboxane B2. Trypsin treatment or boiling reduced or abolished specific PGE2 binding. PGE2 stimulated cAMP formation in the 2,500-g fraction, with an approximate Km of 1 X 10(-6) M, but stimulation of adenylate cyclase activity by PG was not evident in the 16,000-g or 30,000-g tissue preparations. These results suggest that a specific PGE2-binding site exists in the 16,000-g and 30,000-g fractions of porcine fundic mucosa, although an increase in cAMP-forming capacity could not b of 1 X 10(-6) M, but stimulation of adenylate cyclase activity by PG was not evident in the 16,000-g or 30,000-g tissue preparations. These results suggest that a specific PGE2-binding site exists in the 16,000-g and 30,000-g fractions of porcine fundic mucosa, although an increase in cAMP-forming capacity could not b of 1 X 10(-6) M, but stimulation of adenylate cyclase activity by PG was not evident in the 16,000-g or 30,000-g tissue preparations. These results suggest that a specific PGE2-binding site exists in the 16,000-g and 30,000-g fractions of porcine fundic mucosa, although an increase in cAMP-forming capacity could not be localized in these fractions in vitro.


2020 ◽  
Vol 9 (9) ◽  
pp. 2811
Author(s):  
Michael Schreinlechner ◽  
Maria Noflatscher ◽  
Daniela Lener ◽  
Axel Bauer ◽  
Rudolf Kirchmair ◽  
...  

Background/Objectives: Inflammation represents a cornerstone in the development of atherosclerosis and early detection is essential to avoid cardiovascular events. Biomarkers like interleukin-1 beta, interleukin-6, or high sensitivity CRP (hs-CRP) have been investigated intensively in this field. Since they have several limitations, additional biomarkers are needed for cardiovascular risk stratification. The acute phase protein, neutrophil gelatinase-associated lipocalin (NGAL), modulates inflammation and is elevated in cardiovascular disease (CVD). Moreover, it contributes to plaque destabilization. Methods: In this prospective, single-center study, we included 323 asymptomatic patients with at least one cardiovascular risk factor or established CVD. NGAL levels were measured in plasma samples using a commercially available ELISA. Carotid, femoral, and total atherosclerotic plaque volumes (PV) were measured using a 3D ultrasound system (Philips iU22). Patients were separated into a low (n = 243) and high (n = 80) total PV group. Results: NGAL was significantly higher in patients with high total PV versus patients with low total PV. The NGAL amplitude for the prediction of high total PV was significantly higher when compared with hs-CRP. A high predictive value could also be observed for patients without established CVD. Conclusion: NGAL seems to be a promising biomarker for the identification of asymptomatic patients with atherosclerotic disease.


1998 ◽  
Vol 275 (1) ◽  
pp. H145-H150 ◽  
Author(s):  
Mohammad M. H. Khan ◽  
Satya P. Kunapuli ◽  
Yingzhang Lin ◽  
Abraham Majluf-Cruz ◽  
Raul A. Dela Cadena ◽  
...  

The binding of high-molecular-weight kininogen (HK) to neutrophils (polymorphonuclear leukocytes, PMN) is required for the stimulation of aggregation and degranulation by human plasma kallikrein as well as the displacement of fibrinogen from this cell surface. The putative receptor for HK is the leukocyte integrin αMβ2, and domains 3 (D3) and 5 (D5) of HK form its binding site. To further map the binding sites on HK for PMN, we used D3 recombinant exon products and designed peptides from D3 and D5. In D3, a heptapeptide, Leu271-Ala277, from exon 7 product, and a peptide, Cys333-Cys352, from exon 9 product can inhibit binding of kininogen to PMN. Two contiguous peptides from D5 in the histidine-glycine-rich region, Gly442-Lys458and Phe459-Lys478, each inhibit the binding of HK to PMN. This study has thus delineated three noncontiguous surface-oriented sequences on HK, which together comprise all or most of the binding site for human PMN.


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