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Ali DE, El-Shiekh RA, El Sawy MA, Khalifa AA, Elblehi SS, Elsokkary NH, Ali MA. In vivo anti-gastric ulcer activity of 7-O-methyl aromadendrin and sakuranetin via mitigating inflammatory and oxidative stress trails. JOURNAL OF ETHNOPHARMACOLOGY 2024; 335:118617. [PMID: 39053715 DOI: 10.1016/j.jep.2024.118617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 07/10/2024] [Accepted: 07/22/2024] [Indexed: 07/27/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Eucalyptus genus has been used for a very long time in conventional treatment as an anti-ulcer remedy. AIM OF THE STUDY The study aimed to explore the gastroprotective potential of 7-O-methyl aromadendrin (7-OMA), and sakuranetin (SKN) in comparison with omeprazole. The study tackled the contribution of their anti-inflammatory, antioxidant, and antiapoptotic capabilities to their anti-gastric ulcer effects. MATERIALS AND METHODS An ethanol-induced gastric ulcer model in rats was adopted and the consequences were confirmed by a molecular docking study. RESULTS The oral pretreatment of rats 1 h before ethanol using omeprazole (20 mg/kg) or 7-OMA (20 or 40 mg/kg) or SKN (20 or 40 mg/kg) exhibited gastroprotective and anti-inflammatory properties to different extents. These amendments witnessed as restorations in the stomach histological architecture in H and E-stained sections, mucus content in periodic acid-Schiff (PAS) stained sections with increased cellular proliferation, as demonstrated by increased immunohistochemical staining of PCNA, and increments in stomach COX-1 activity and eNOS. The highest dose of SKN showed the best corrections to reach 4.8, 1.8, and 2.1 folds increase in PAS, COX-1 and eNOS, respectively as compared to the untreated ethanol-induced gastric ulcer group; effects that were comparable to that of omeprazole. Moreover, reductions in COX-2 activity, and the protein expression of NF-κB, IL-6, TNF-α and NOx, in addition to the gene expression of inducible iNOS were also noted. Moreover, the antioxidant and antiapoptotic capabilities of omeprazole, 7-OMA, and SKN were perceived. SKN (40 mg/kg) succeeded to show the unsurpassed results to reach 293.6%, 237.1%, 274.7%, 248.2%, and 175.4% in total and reduced GSH, catalase, SOD, and Bcl2, respectively, as well as 50.0%, 46.8%, and 52.1 % in oxidized GSSG, TBARS and caspase-3, respectively. The gastroprotective potential of the tested compounds can be assigned to their anti-inflammatory, antioxidant and antiapoptotic properties.7-OMA and SKN were studied using molecular docking into the binding sites of the most significant inflammatory targets, including COX-2, TNF-α, iNOS, and NF-κB. Pharmacokinetic and physicochemical parameters in silico were appropriate. CONCLUSION The prophylactic use of 7-OMA and SKN could be considered as an add-on to recurrent gastric ulcers and might influence its therapeutic approaches.
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Affiliation(s)
- Dalia E Ali
- Department of Pharmacognosy and Natural Products, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, Egypt
| | - Riham A El-Shiekh
- Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.
| | - Maged A El Sawy
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, Egypt
| | - Asmaa A Khalifa
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, Egypt
| | - Samar S Elblehi
- Department of Pathology, Faculty of Veterinary Medicine, Alexandria University, Alexandria, Egypt
| | - Nahed H Elsokkary
- Department of Physiology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Mennatallah A Ali
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Pharos University in Alexandria, Alexandria, Egypt
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2
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Elucidation of the underlying mechanism of Hua-ban decoction in alleviating acute lung injury by an integrative approach of network pharmacology and experimental verification. Mol Immunol 2023; 156:85-97. [PMID: 36913767 DOI: 10.1016/j.molimm.2023.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/29/2022] [Accepted: 02/27/2023] [Indexed: 03/13/2023]
Abstract
The pathogenic hyper-inflammatory response has been regarded as the major cause of the severity and death related to acute lung injury (ALI). Hua-ban decoction (HBD) is a classical prescription in traditional Chinese medicine (TCM). It has been extensively used to treat inflammatory diseases; however, its bioactive components and therapeutic mechanisms remain unclear. Here, we established a lipopolysaccharide (LPS)-induced ALI model that presents a hyperinflammatory process to explore the pharmaco-dynamic effect and underlying molecular mechanism of HBD on ALI. In vivo, we confirmed that in LPS-induced ALI mice, HBD improved pulmonary injury by via down-regulating the expression of proinflammatory cytokines, including IL-6, TNF-α, and macrophage infiltration, as well as macrophage M1 polarization. Moreover, in vitro experiments in LPS-stimulated macrophages demonstrated that the potential bioactive compounds of HBD inhibited the secretion of IL-6 and TNF-α. Mechanically, the data revealed that HBD treatment of LPS-induced ALI acted via NF-κB pathway, which regulated macrophage M1 polarization. Additionally, two major HBD compounds, i.e., quercetin and kaempferol, showed a high binding affinity with p65 and IkBα. In conclusion, the data obtained in this study demonstrated the therapeutic effects of HBD, which indicates the possibility for the development of HBD as a potential treatment for ALI.
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3
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Pan W, Meshcheryakov VA, Li T, Wang Y, Ghosh G, Wang VYF. Structures of NF-κB p52 homodimer-DNA complexes rationalize binding mechanisms and transcription activation. eLife 2023; 12:e86258. [PMID: 36779700 PMCID: PMC9991059 DOI: 10.7554/elife.86258] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 02/07/2023] [Indexed: 02/14/2023] Open
Abstract
The mammalian NF-κB p52:p52 homodimer together with its cofactor Bcl3 activates transcription of κB sites with a central G/C base pair (bp), while it is inactive toward κB sites with a central A/T bp. To understand the molecular basis for this unique property of p52, we have determined the crystal structures of recombinant human p52 protein in complex with a P-selectin(PSel)-κB DNA (5'-GGGGTGACCCC-3') (central bp is underlined) and variants changing the central bp to A/T or swapping the flanking bp. The structures reveal a nearly two-fold widened minor groove in the central region of the DNA as compared to all other currently available NF-κB-DNA complex structures, which have a central A/T bp. Microsecond molecular dynamics (MD) simulations of free DNAs and p52 bound complexes reveal that free DNAs exhibit distinct preferred conformations, and p52:p52 homodimer induces the least amount of DNA conformational changes when bound to the more transcriptionally active natural G/C-centric PSel-κB, but adopts closed conformation when bound to the mutant A/T and swap DNAs due to their narrowed minor grooves. Our binding assays further demonstrate that the fast kinetics favored by entropy is correlated with higher transcriptional activity. Overall, our studies have revealed a novel conformation for κB DNA in complex with NF-κB and pinpoint the importance of binding kinetics, dictated by DNA conformational and dynamic states, in controlling transcriptional activation for NF-κB.
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Affiliation(s)
- Wenfei Pan
- Faculty of Health Sciences, University of MacauTaipaChina
| | | | - Tianjie Li
- Department of Physics, Chinese University of Hong KongShatinHong Kong
| | - Yi Wang
- Department of Physics, Chinese University of Hong KongShatinHong Kong
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California, San DiegoLa JollaUnited States
| | - Vivien Ya-Fan Wang
- Faculty of Health Sciences, University of MacauTaipaChina
- MoE Frontiers Science Center for Precision Oncology, University of MacauTaipaMacao
- Cancer Centre, Faculty of Health Sciences, University of MacauTaipaChina
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4
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Baughman HER, Narang D, Chen W, Villagrán Suárez AC, Lee J, Bachochin MJ, Gunther TR, Wolynes PG, Komives EA. An intrinsically disordered transcription activation domain increases the DNA binding affinity and reduces the specificity of NFκB p50/RelA. J Biol Chem 2022; 298:102349. [PMID: 35934050 PMCID: PMC9440430 DOI: 10.1016/j.jbc.2022.102349] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 12/03/2022] Open
Abstract
Many transcription factors contain intrinsically disordered transcription activation domains (TADs), which mediate interactions with coactivators to activate transcription. Historically, DNA-binding domains and TADs have been considered as modular units, but recent studies have shown that TADs can influence DNA binding. Whether these results can be generalized to more TADs is not clear. Here, we biophysically characterized the NFκB p50/RelA heterodimer including the RelA TAD and investigated the TAD's influence on NFκB-DNA interactions. In solution, we show the RelA TAD is disordered but compact, with helical tendency in two regions that interact with coactivators. We determined that the presence of the TAD increased the stoichiometry of NFκB-DNA complexes containing promoter DNA sequences with tandem κB recognition motifs by promoting the binding of NFκB dimers in excess of the number of κB sites. In addition, we measured the binding affinity of p50/RelA for DNA containing tandem κB sites and single κB sites. While the presence of the TAD enhanced the binding affinity of p50/RelA for all κB sequences tested, it also increased the affinity for nonspecific DNA sequences by over 10-fold, leading to an overall decrease in specificity for κB DNA sequences. In contrast, previous studies have generally reported that TADs decrease DNA-binding affinity and increase sequence specificity. Our results reveal a novel function of the RelA TAD in promoting binding to nonconsensus DNA, which sheds light on previous observations of extensive nonconsensus DNA binding by NFκB in vivo in response to strong inflammatory signals.
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Affiliation(s)
- Hannah E R Baughman
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Dominic Narang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Wei Chen
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Amalia C Villagrán Suárez
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Joan Lee
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Maxwell J Bachochin
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Tristan R Gunther
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
| | - Peter G Wolynes
- Department of Chemistry and Center for Theoretical Biological Physics, Rice University, Houston, Texas, USA
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA.
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5
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Chen W, Lu W, Wolynes PG, Komives E. Single-molecule conformational dynamics of a transcription factor reveals a continuum of binding modes controlling association and dissociation. Nucleic Acids Res 2021; 49:11211-11223. [PMID: 34614173 PMCID: PMC8565325 DOI: 10.1093/nar/gkab874] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 09/10/2021] [Accepted: 09/22/2021] [Indexed: 12/24/2022] Open
Abstract
Binding and unbinding of transcription factors to DNA are kinetically controlled to regulate the transcriptional outcome. Control of the release of the transcription factor NF-κB from DNA is achieved through accelerated dissociation by the inhibitor protein IκBα. Using single-molecule FRET, we observed a continuum of conformations of NF-κB in free and DNA-bound states interconverting on the subseconds to minutes timescale, comparable to in vivo binding on the seconds timescale, suggesting that structural dynamics directly control binding kinetics. Much of the DNA-bound NF-κB is partially bound, allowing IκBα invasion to facilitate DNA dissociation. IκBα induces a locked conformation where the DNA-binding domains of NF-κB are too far apart to bind DNA, whereas a loss-of-function IκBα mutant retains the NF-κB conformational ensemble. Overall, our results suggest a novel mechanism with a continuum of binding modes for controlling association and dissociation of transcription factors.
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Affiliation(s)
- Wei Chen
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
| | - Wei Lu
- Center for Theoretical Biological Physics, Departments of Chemistry, Physics, and Biosciences, Rice University, Houston, Texas 77005, USA
| | - Peter G Wolynes
- Center for Theoretical Biological Physics, Departments of Chemistry, Physics, and Biosciences, Rice University, Houston, Texas 77005, USA
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, USA
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6
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Kanapeckaitė A, Beaurivage C, Jančorienė L, Mažeikienė A. In silico drug discovery for a complex immunotherapeutic target - human c-Rel protein. Biophys Chem 2021; 276:106593. [PMID: 34087524 DOI: 10.1016/j.bpc.2021.106593] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/28/2021] [Accepted: 04/12/2021] [Indexed: 12/22/2022]
Abstract
Target evaluation and rational drug design rely on identifying and characterising small-molecule binding sites on therapeutically relevant target proteins. Immunotherapeutics development is especially challenging because of complex disease etiology and heterogenous nature of targets. c-Rel protein, a promising target in many human inflammatory and cancer pathologies, was selected as a case study for an effective in silico screening platform development since this transcription factor currently has no successful therapeutic inhibitors or modulators. This study introduces a novel in silico screening approach to probe binding sites using structural validation sets, molecular modelling and describes a method of a computer-aided drug design when a crystal structure is not available for the target of interest. In addition, we showed that binding sites can be analysed with the machine learning as well as molecular simulation approaches to help assess and systematically analyse how drug candidates can exert their mode of action. Finally, this cutting-edge approach was subjected to a high through-put virtual screen of selected 34 M drug-like compounds filtered from a library of 659 M compounds by identifying the most promising structures and proposing potential action mechanisms for the future development of highly selective human c-Rel inhibitors and/or modulators.
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Affiliation(s)
| | | | - Ligita Jančorienė
- Vilnius University Medical Faculty InsTtute of Clinical Medicine, Clinic of InfecTous Diseases and Dermatovenerology, Santariškių str. 14, 08406 Vilnius, Lithuania
| | - Asta Mažeikienė
- Department of Physiology, Biochemistry, Microbiology and Laboratory Medicine, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, M. K. Čiurlionio g. 21, LT-03101, Vilnius, Lithuania
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7
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Zhou Y, Zhong B, Min X, Hou Y, Lin L, Wu Q, Shi J, Chen X. Therapeutic potential of isobavachalcone, a natural flavonoid, in murine experimental colitis by inhibiting NF-κB p65. Phytother Res 2021; 35:5861-5870. [PMID: 34435401 DOI: 10.1002/ptr.7246] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 12/14/2022]
Abstract
The incidence of ulcerative colitis (UC), one of the two types of inflammatory bowel disease, is increasing in many countries. Various natural products have been demonstrated with therapeutic potentials for UC. Herein, the therapeutic effects and mechanisms of isobavachalcone (IBC), a natural chalcone, were evaluated in dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The results demonstrated that IBC treatment significantly improved the clinical symptoms, assessed by the disease activity index (DAI) scores and the histological changes of the colon. The levels of myeloperoxidase (MPO), TNF-α, IL-6, IL-1β, and prostaglandin E2 (PGE2) in colon tissues were suppressed by IBC. The upregulation of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and NF-κB p65 in colon tissues were reversed by IBC as well. Furthermore, IBC significantly inhibited LPS-triggered secretion of TNF-α, IL-6, and nitrite, and nuclear translocation of NF-κB p65, in RAW264.7 cells. The luciferase reporter assay indicated that IBC significantly inhibited LPS-triggered transcription of toll-like receptor 4 (TLR4). Molecular docking results showed that the binding pocket of IBC was adjacent to Ser276 of p65-p50 heterodimer and IBC could form H-bond with Thr191. Collectively, these results demonstrated that IBC ameliorated colitis in mice possibly through inhibition of NF-κB p65.
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Affiliation(s)
- Yishan Zhou
- Key Lab for Pharmacology of Ministry of Education, Department of Pharmacology, Zunyi Medical University, Zunyi, China
| | - Bingling Zhong
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Xiangjing Min
- Key Lab for Pharmacology of Ministry of Education, Department of Pharmacology, Zunyi Medical University, Zunyi, China
| | - Ying Hou
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Ligen Lin
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China.,Department of Pharmaceutical Sciences, Faculty of Health Sciences, University of Macau, Macau, China
| | - Qin Wu
- Key Lab for Pharmacology of Ministry of Education, Department of Pharmacology, Zunyi Medical University, Zunyi, China
| | - Jingshan Shi
- Key Lab for Pharmacology of Ministry of Education, Department of Pharmacology, Zunyi Medical University, Zunyi, China
| | - Xiuping Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China.,Department of Pharmaceutical Sciences, Faculty of Health Sciences, University of Macau, Macau, China
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8
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Biancalana M, Natan E, Lenardo MJ, Fersht AR. NF-κB Rel subunit exchange on a physiological timescale. Protein Sci 2021; 30:1818-1832. [PMID: 34089216 DOI: 10.1002/pro.4134] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 12/21/2022]
Abstract
The Rel proteins of the NF-κB complex comprise one of the most investigated transcription factor families, forming a variety of hetero- or homodimers. Nevertheless, very little is known about the fundamental kinetics of NF-κB complex assembly, or the inter-conversion potential of dimerised Rel subunits. Here, we examined an unexplored aspect of NF-κB dynamics, focusing on the dissociation and reassociation of the canonical p50 and p65 Rel subunits and their ability to form new hetero- or homodimers. We employed a soluble expression system to enable the facile production of NF-κB Rel subunits, and verified these proteins display canonical NF-κB nucleic acid binding properties. Using a combination of biophysical techniques, we demonstrated that, at physiological temperatures, homodimeric Rel complexes routinely exchange subunits with a half-life of less than 10 min. In contrast, we found a dramatic preference for the formation of the p50/p65 heterodimer, which demonstrated a kinetic stability of at least an order of magnitude greater than either homodimer. These results suggest that specific DNA targets of either the p50 or p65 homodimers can only be targeted when these subunits are expressed exclusively, or with the intervention of additional post-translational modifications. Together, this work implies a new model of how cells can modulate NF-κB activity by fine-tuning the relative proportions of the p50 and p65 proteins, as well as their time of expression. This work thus provides a new quantitative interpretation of Rel dimer distribution in the cell, particularly for those who are developing mathematical models of NF-κB activity.
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Affiliation(s)
- Matthew Biancalana
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.,Molecular Development of the Immune System Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | | | - Michael J Lenardo
- Molecular Development of the Immune System Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Alan R Fersht
- Medical Research Council Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
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9
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Raza T, Dhaka N, Joseph D, Dadhwal P, Kakita VMR, Atreya HS, Mukherjee SP. Insights into the NF-κB-DNA Interaction through NMR Spectroscopy. ACS OMEGA 2021; 6:12877-12886. [PMID: 34056439 PMCID: PMC8154232 DOI: 10.1021/acsomega.1c01299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
Transcription factors bind specifically to their target elements in the genome, eliciting specific gene expression programs. The nuclear factor-κB (NF-κB) system is a family of proteins comprising inducible transcription activators, which play a critical role in inflammation and cancer. The NF-κB members function as dimers with each monomeric unit binding the κB-DNA. Despite the available structures of the various NF-κB dimers in complex with the DNA, the structural features of these dimers in the nucleic acid-free form are not well-characterized. Using solution NMR spectroscopy, we characterize the structural features of 73.1 kDa p50 subunit of the NF-κB homodimer in the DNA-free form and compare it with the κB DNA-bound form of the protein. The study further reveals that in the nucleic acid-free form, the two constituent domains of p50, the N-terminal and the dimerization domains, are structurally independent of each other. However, in a complex with the κB DNA, both the domains of p50 act as a single unit. The study also provides insights into the mechanism of κB DNA recognition by the p50 subunit of NF-κB.
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Affiliation(s)
- Tahseen Raza
- Department
of Biotechnology, Indian Institute of Technology
Roorkee, Roorkee, Uttarakhand 247667, India
| | - Nitin Dhaka
- Department
of Biotechnology, Indian Institute of Technology
Roorkee, Roorkee, Uttarakhand 247667, India
| | - David Joseph
- NMR
Research Centre, Indian Institute of Science
Bengaluru, Bengaluru, Karnataka 560012, India
| | - Prikshat Dadhwal
- Department
of Biotechnology, Indian Institute of Technology
Roorkee, Roorkee, Uttarakhand 247667, India
| | - Veera Mohana Rao Kakita
- UM-DAE-Centre
for Excellence in Basic Sciences, University
of Mumbai, Kalina Campus, Mumbai, Maharashtra 400098, India
| | - Hanudatta S. Atreya
- NMR
Research Centre, Indian Institute of Science
Bengaluru, Bengaluru, Karnataka 560012, India
| | - Sulakshana P. Mukherjee
- Department
of Biotechnology, Indian Institute of Technology
Roorkee, Roorkee, Uttarakhand 247667, India
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10
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Kumar M, Dhaka N, Raza T, Dadhwal P, Atreya HS, Mukherjee SP. Domain Stability Regulated through the Dimer Interface Controls the Formation Kinetics of a Specific NF-κB Dimer. Biochemistry 2021; 60:513-523. [PMID: 33555182 DOI: 10.1021/acs.biochem.0c00837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NF-κB family of transcription factors is a key regulator of the immune response in the vertebrates. The family comprises five proteins that function as dimers formed in various combinations among the members, with the RelA-p50 dimer being physiologically the most abundant. While most of the 15 possible dimers are scarcely present in the cell with some remaining experimentally undetected to date, there are specific gene sets that are only activated by certain sparsely populated NF-κB dimers. The mechanism of transcription activation of such specific genes that are activated only by specific NF-κB dimers remains unclear. Here we show that the dimer interfacial residues control the stabilization of the global hydrogen bond network of the NF-κB dimerization domain, which, in turn, controls the thermodynamic stabilization of different NF-κB dimers. The relatively low thermodynamic stability of the RelA-RelA homodimer is critical as it facilitates the formation of the more stable RelA-p50 heterodimer. Through the modulation of the thermodynamic stability of the RelA-RelA homodimer, the kinetics of the RelA-p50 heterodimer formation can be regulated. This phenomenon provides an insight into the mechanism of RelA-RelA specific target gene regulation in physiology.
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Affiliation(s)
- Manish Kumar
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Nitin Dhaka
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Tahseen Raza
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Prikshat Dadhwal
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Hanudatta S Atreya
- NMR Research Centre, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Sulakshana P Mukherjee
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
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11
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Kumar M, Dadhwal P, Atreya HS, Mukherjee SP. Backbone resonance assignments of the dimeric domain of the p50 NF-kappaB subunit. BIOMOLECULAR NMR ASSIGNMENTS 2020; 14:9-11. [PMID: 31446566 DOI: 10.1007/s12104-019-09912-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/21/2019] [Indexed: 06/10/2023]
Abstract
The Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) is a family of transcription factor recognizing a 9-11 base pair kappaB sites on the promoter/enhancer region of their target genes. The family comprises of five members forming dimers amongst themselves in various combinations. Here we report the backbone resonance assignments of the 24 kDa homodimer of the p50 subunit of NF-kappaB. This is the first step towards understanding the mechanism of dimer formation in solution. The secondary structure derived from the chemical shifts for the dimer is largely consistent with that observed in the available crystal structures of the protein in DNA-bound form.
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Affiliation(s)
- Manish Kumar
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 247667, India
| | - Prikshat Dadhwal
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 247667, India
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
| | - Hanudatta S Atreya
- NMR Research Centre, Indian Institute of Science Bangalore, Bangalore, Karnataka, India
| | - Sulakshana P Mukherjee
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 247667, India.
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12
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Ali A, Shah FA, Zeb A, Malik I, Alvi AM, Alkury LT, Rashid S, Hussain I, Ullah N, Khan AU, Koh PO, Li S. NF-κB Inhibitors Attenuate MCAO Induced Neurodegeneration and Oxidative Stress-A Reprofiling Approach. Front Mol Neurosci 2020; 13:33. [PMID: 32292329 PMCID: PMC7121334 DOI: 10.3389/fnmol.2020.00033] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 02/12/2020] [Indexed: 12/23/2022] Open
Abstract
Stroke is the leading cause of morbidity and mortality worldwide. About 87% of stroke cases are ischemic, which disrupt the physiological activity of the brain, thus leading to a series of complex pathophysiological events. Despite decades of research on neuroprotectants to probe for suitable therapies against ischemic stroke, no successful results have been obtained, and new alternative approaches are urgently required in order to combat this pathological torment. To address these problems, drug repositioning/reprofiling is explored extensively. Drug repurposing aims to identify new uses for already established drugs, and this makes it an attractive commercial strategy. Nuclear factor-kappa beta (NF-κB) is reported to be involved in many physiological and pathological conditions, such as neurodegeneration, neuroinflammation, and ischemia/reperfusion (I/R) injury. In this study, we examined the neuroprotective effects of atorvastatin, cephalexin, and mycophenolate against the NF-κB in ischemic stroke, as compared to the standard NF-κB inhibitor caeffic acid phenethyl ester (CAPE). An in-silico docking analysis was performed and their potential neuroprotective activities in the in vivo transient middle cerebral artery occlusion (t-MCAO) rat model was examined. The percent (%) infarct area and 28-point composite neuro score were examined, and an immunohistochemical analysis (IHC) and enzyme-linked immunosorbent assay (ELISA) were further performed to validate the neuroprotective role of these compounds in stroke as well as their potential as antioxidants. Our results demonstrated that these novels NF-κB inhibitors could attenuate ischemic stroke-induced neuronal toxicity by targeting NF-κB, a potential therapeutic approach in ischemic stroke.
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Affiliation(s)
- Awais Ali
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Fawad Ali Shah
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Alam Zeb
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Imran Malik
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Arooj Mohsin Alvi
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Lina Tariq Alkury
- College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
| | - Sajid Rashid
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Ishtiaq Hussain
- Department of Pharmacy, Abbottabad University of Science and Technology, Khyber Pakhtunkhwa, Pakistan
| | - Najeeb Ullah
- Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen, China
| | - Arif Ullah Khan
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Phil Ok Koh
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea
| | - Shupeng Li
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen, China
- Centre for Addiction and Mental Health, Campbell Research Institute, Toronto, ON, Canada
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13
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Host Transcription Factors in Hepatitis B Virus RNA Synthesis. Viruses 2020; 12:v12020160. [PMID: 32019103 PMCID: PMC7077322 DOI: 10.3390/v12020160] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/27/2020] [Accepted: 01/28/2020] [Indexed: 02/06/2023] Open
Abstract
The hepatitis B virus (HBV) chronically infects over 250 million people worldwide and is one of the leading causes of liver cancer and hepatocellular carcinoma. HBV persistence is due in part to the highly stable HBV minichromosome or HBV covalently closed circular DNA (cccDNA) that resides in the nucleus. As HBV replication requires the help of host transcription factors to replicate, focusing on host protein–HBV genome interactions may reveal insights into new drug targets against cccDNA. The structural details on such complexes, however, remain poorly defined. In this review, the current literature regarding host transcription factors’ interactions with HBV cccDNA is discussed.
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14
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Mulero MC, Wang VYF, Huxford T, Ghosh G. Genome reading by the NF-κB transcription factors. Nucleic Acids Res 2019; 47:9967-9989. [PMID: 31501881 PMCID: PMC6821244 DOI: 10.1093/nar/gkz739] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/05/2019] [Accepted: 08/21/2019] [Indexed: 12/25/2022] Open
Abstract
The NF-κB family of dimeric transcription factors regulates transcription by selectively binding to DNA response elements present within promoters or enhancers of target genes. The DNA response elements, collectively known as κB sites or κB DNA, share the consensus 5'-GGGRNNNYCC-3' (where R, Y and N are purine, pyrimidine and any nucleotide base, respectively). In addition, several DNA sequences that deviate significantly from the consensus have been shown to accommodate binding by NF-κB dimers. X-ray crystal structures of NF-κB in complex with diverse κB DNA have helped elucidate the chemical principles that underlie target selection in vitro. However, NF-κB dimers encounter additional impediments to selective DNA binding in vivo. Work carried out during the past decades has identified some of the barriers to sequence selective DNA target binding within the context of chromatin and suggests possible mechanisms by which NF-κB might overcome these obstacles. In this review, we first highlight structural features of NF-κB:DNA complexes and how distinctive features of NF-κB proteins and DNA sequences contribute to specific complex formation. We then discuss how native NF-κB dimers identify DNA binding targets in the nucleus with support from additional factors and how post-translational modifications enable NF-κB to selectively bind κB sites in vivo.
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Affiliation(s)
- Maria Carmen Mulero
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Vivien Ya-Fan Wang
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau SAR, China
| | - Tom Huxford
- Structural Biochemistry Laboratory, Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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15
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Ivanova IG, Perkins ND. Hypoxia induces rapid, STAT3 and ROS dependent, mitochondrial translocation of RelA(p65) and IκBα. Biosci Rep 2019; 39:BSR20192101. [PMID: 31484794 PMCID: PMC6746997 DOI: 10.1042/bsr20192101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/15/2019] [Accepted: 08/21/2019] [Indexed: 12/02/2022] Open
Abstract
The nuclear factor-κB (NF-κB) family of transcription factors can directly or indirectly regulate many important areas of biology, including immunity, inflammation and cell survival. One intriguing aspect of NF-κB crosstalk with other cell signalling pathways is its regulation of mitochondrial biology, including biogenesis, metabolism and apoptosis. In addition to regulating the expression of mitochondrial genes encoded in the nucleus, NF-κB signalling components are also found within mitochondria themselves and associated with mitochondrial DNA. However, complete biochemical analysis of mitochondrial and sub-mitochondrial localisation of all NF-κB subunits has not been undertaken. Here, we show that only the RelA NF-κB subunit and its inhibitor IκBα reside within mitochondria, whilst p50 is found in the endoplasmic reticulum (ER). Fractionation of mitochondria revealed that only RelA was found in the mitoplast, the location of the mtDNA. We demonstrate that hypoxia leads to a very rapid but transient accumulation of RelA and IκBα in mitochondria. This effect required reactive oxygen species (ROS) but was not dependent on the hypoxia sensing transcription factor subunit HIF1α or intracellular Ca2+ release. We also observed rapid mitochondrial localisation of transcription factor STAT3 following hypoxia. Inhibition of STAT3 blocked RelA and IκBα mitochondrial localisation revealing a previously unknown aspect of crosstalk between these key cellular regulators.
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Affiliation(s)
- Iglika G Ivanova
- Faculty of Medical Sciences, Institute for Cell and Molecular Biosciences (ICaMB), Newcastle University, Newcastle Upon Tyne, U.K
| | - Neil D Perkins
- Faculty of Medical Sciences, Institute for Cell and Molecular Biosciences (ICaMB), Newcastle University, Newcastle Upon Tyne, U.K.
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16
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Kanofsky K, Riggers J, Staar M, Strauch CJ, Arndt LC, Hehl R. A strong NF-κB p65 responsive cis-regulatory sequence from Arabidopsis thaliana interacts with WRKY40. PLANT CELL REPORTS 2019; 38:1139-1150. [PMID: 31197450 DOI: 10.1007/s00299-019-02433-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/28/2019] [Indexed: 06/09/2023]
Abstract
Transcription factors from mammals and plants, which play a role in innate immunity, interact with the same microbe-associated molecular pattern (MAMP)-responsive sequences from Arabidopsis thaliana. The interaction of mouse NF-κB p65 with MAMP-responsive sequences containing the core motif GACTTT of the WT-box was investigated. This revealed one sequence, derived from the promoter of the A. thaliana gene At1g76960, a gene with unknown function, to activate NF-κB p65 dependent reporter gene expression in plant cells very strongly. A bioinformatic analysis predicts three putative NF-κB p65 binding sites in this sequence and all three sites are required for reporter gene activation and binding. The sequence is one of the weakest MAMP-responsive sequences previously isolated, but the introduction of a GCC-box increases its MAMP responsivity in combination with upstream WT-box sequences. Although a bioinformatic analysis of the unmutated cis-sequence only predicts NF-κB p65 binding, A. thaliana WRKY40 was selected in a yeast one-hybrid screen. WRKY40, which is a transcriptional repressor, requires the sequence TTTTCTA for direct binding. This sequence is similar to the WK-box TTTTCCAC, previously shown to interact with tobacco NtWRKY12. In summary, this work supports the similarity in binding site recognition between NF-κB and WRKY factors.
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Affiliation(s)
- Konstantin Kanofsky
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Jasmin Riggers
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Marcel Staar
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Claudia Janina Strauch
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Laureen Christin Arndt
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Reinhard Hehl
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany.
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17
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Silva VS, Vergara FM, Seito LN, Antunes D, Santos LHS, Henriques MG, Caffarena ER. Thiophenacetamide as a potential modulator to NF-κB: structure and dynamics study using in silico and molecular biology assays. J Biomol Struct Dyn 2019; 37:4395-4406. [DOI: 10.1080/07391102.2018.1552623] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Vanessa S. Silva
- PROCC, Grupo de Biofísica Computacional e Modelagem Molecular, Fiocruz, Rio de Janeiro, Brazil
| | - Fatima M. Vergara
- Instituto de Tecnologia em Fármacos – Farmanguinhos, Laboratório de Farmacologia Aplicada, Fiocruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas (INCT-IDPN), Rio de Janeiro, Brazil
- Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Fiocruz, Rio de Janeiro, Brazil
| | - Leonardo N. Seito
- Instituto de Tecnologia em Fármacos – Farmanguinhos, Laboratório de Farmacologia Aplicada, Fiocruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas (INCT-IDPN), Rio de Janeiro, Brazil
| | - Deborah Antunes
- PROCC, Grupo de Biofísica Computacional e Modelagem Molecular, Fiocruz, Rio de Janeiro, Brazil
| | - Lucianna H. S. Santos
- Laboratório de Modelagem Molecular e Planejamento de Fármacos, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Maria G. Henriques
- Instituto de Tecnologia em Fármacos – Farmanguinhos, Laboratório de Farmacologia Aplicada, Fiocruz, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia de Inovação em Doenças de Populações Negligenciadas (INCT-IDPN), Rio de Janeiro, Brazil
| | - Ernesto R. Caffarena
- PROCC, Grupo de Biofísica Computacional e Modelagem Molecular, Fiocruz, Rio de Janeiro, Brazil
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18
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Mulero MC, Huxford T, Ghosh G. NF-κB, IκB, and IKK: Integral Components of Immune System Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1172:207-226. [PMID: 31628658 DOI: 10.1007/978-981-13-9367-9_10] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The NF-κB (Nuclear Factor kappa B) transcription factor plays crucial roles in the regulation of numerous biological processes including development of the immune system, inflammation, and innate and adaptive immune responses. Control over the immune cell functions of NF-κB results from signaling through one of two different routes: the canonical and noncanonical NF-κB signaling pathways. Present at the end of both pathways are the proteins NF-κB, IκB, and the IκB kinase (IKK). These proteins work together to deliver the myriad outcomes that influence context-dependent transcriptional control in immune cells. In the present chapter, we review the structural information available on NF-κB, IκB, and IKK, the critical terminal components of the NF-κB signaling, in relation to their physiological function.
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Affiliation(s)
- Maria Carmen Mulero
- Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Tom Huxford
- Structural Biochemistry Laboratory, Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA, 92182, USA
| | - Gourisankar Ghosh
- Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
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19
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Hudson WH, Vera IMSD, Nwachukwu JC, Weikum ER, Herbst AG, Yang Q, Bain DL, Nettles KW, Kojetin DJ, Ortlund EA. Cryptic glucocorticoid receptor-binding sites pervade genomic NF-κB response elements. Nat Commun 2018; 9:1337. [PMID: 29626214 PMCID: PMC5889392 DOI: 10.1038/s41467-018-03780-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/13/2018] [Indexed: 12/19/2022] Open
Abstract
Glucocorticoids (GCs) are potent repressors of NF-κB activity, making them a preferred choice for treatment of inflammation-driven conditions. Despite the widespread use of GCs in the clinic, current models are inadequate to explain the role of the glucocorticoid receptor (GR) within this critical signaling pathway. GR binding directly to NF-κB itself-tethering in a DNA binding-independent manner-represents the standing model of how GCs inhibit NF-κB-driven transcription. We demonstrate that direct binding of GR to genomic NF-κB response elements (κBREs) mediates GR-driven repression of inflammatory gene expression. We report five crystal structures and solution NMR data of GR DBD-κBRE complexes, which reveal that GR recognizes a cryptic response element between the binding footprints of NF-κB subunits within κBREs. These cryptic sequences exhibit high sequence and functional conservation, suggesting that GR binding to κBREs is an evolutionarily conserved mechanism of controlling the inflammatory response.
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Affiliation(s)
- William H Hudson
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, 30322, USA
- Discovery and Developmental Therapeutics, Winship Cancer Institute, Atlanta, Georgia, 30322, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, 30322, USA
| | - Ian Mitchelle S de Vera
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida, 33458, USA
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, Saint Louis, MO, 63104, USA
| | - Jerome C Nwachukwu
- Department of Integrated Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, 33458, USA
| | - Emily R Weikum
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, 30322, USA
- Discovery and Developmental Therapeutics, Winship Cancer Institute, Atlanta, Georgia, 30322, USA
| | - Austin G Herbst
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, 30322, USA
| | - Qin Yang
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - David L Bain
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045, USA
| | - Kendall W Nettles
- Department of Integrated Structural and Computational Biology, The Scripps Research Institute, Jupiter, Florida, 33458, USA
| | - Douglas J Kojetin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida, 33458, USA
| | - Eric A Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, 30322, USA.
- Discovery and Developmental Therapeutics, Winship Cancer Institute, Atlanta, Georgia, 30322, USA.
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20
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Cooperative Immune Suppression by Escherichia coli and Shigella Effector Proteins. Infect Immun 2018; 86:IAI.00560-17. [PMID: 29339461 DOI: 10.1128/iai.00560-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The enteric attaching and effacing (A/E) pathogens enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC) and the invasive pathogens enteroinvasive E. coli (EIEC) and Shigella encode type III secretion systems (T3SS) used to inject effector proteins into human host cells during infection. Among these are a group of effectors required for NF-κB-mediated host immune evasion. Recent studies have identified several effector proteins from A/E pathogens and EIEC/Shigella that are involved in suppression of NF-κB and have uncovered their cellular and molecular functions. A novel mechanism among these effectors from both groups of pathogens is to coordinate effector function during infection. This cooperativity among effector proteins explains how bacterial pathogens are able to effectively suppress innate immune defense mechanisms in response to diverse classes of immune receptor signaling complexes (RSCs) stimulated during infection.
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21
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Ba X, Boldogh I. 8-Oxoguanine DNA glycosylase 1: Beyond repair of the oxidatively modified base lesions. Redox Biol 2017; 14:669-678. [PMID: 29175754 PMCID: PMC5975208 DOI: 10.1016/j.redox.2017.11.008] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/08/2017] [Accepted: 11/08/2017] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress and the resulting damage to genomic DNA are inevitable consequences of endogenous physiological processes, and they are amplified by cellular responses to environmental exposures. One of the most frequent reactions of reactive oxygen species with DNA is the oxidation of guanine to pre-mutagenic 8-oxo-7,8-dihydroguanine (8-oxoG). Despite the vulnerability of guanine to oxidation, vertebrate genes are primarily embedded in GC-rich genomic regions, and over 72% of the promoters of human genes belong to a class with a high GC content. In the promoter, 8-oxoG may serve as an epigenetic mark, and when complexed with the oxidatively inactivated repair enzyme 8-oxoguanine DNA glycosylase 1, provide a platform for the coordination of the initial steps of DNA repair and the assembly of the transcriptional machinery to launch the prompt and preferential expression of redox-regulated genes. Deviations/variations from this artful coordination may be the etiological links between guanine oxidation and various cellular pathologies and diseases during ageing processes.
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Affiliation(s)
- Xueqing Ba
- The Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, Jilin 130024, China; School of Life Science, Northeast Normal University, Changchun, Jilin 130024, China.
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
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22
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Su P, Liu X, Pang Y, Liu C, Li R, Zhang Q, Liang H, Wang H, Li Q. The archaic roles of the lamprey NF-κB (lj-NF-κB) in innate immune responses. Mol Immunol 2017; 92:21-27. [PMID: 29031044 DOI: 10.1016/j.molimm.2017.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/30/2017] [Accepted: 10/02/2017] [Indexed: 11/27/2022]
Abstract
The nuclear factor-kappa B (NF-κB) is a pleiotropic transcription factor regulating the expression of genes involved in various biological processes including the immune response and inflammation. Lamprey is regarded as a key species to provide meaningful clues for understanding the evolution of immune system; nevertheless, no information about lamprey NF-κB is reported. Thus, we have characterized a NF-κB homolog in lamprey (lj-NF-κB) for the deeper understanding of the role it played in lamprey immune system. The sequence and 3D structure analyses demonstrate that lj-NF-κB contained a Rel homology domain (RHD) and seven ankyrin repeats domains (ANKs), which would exhibit functional similarities to NF-κB superfamily proteins. This hypothesis was further proved by experiments. We found that the RHD of lj-NF-κB could interact with a mammalian κB response element, translocate to the nucleus to modulate gene (IL-6, IL-1β and TNF-α) expression, and the nuclear localization signals (NLS) was essential for the nuclear translocation. Furthermore, the ANKs of lj-NF-κB are the inhibition signal for the RHD of lj-NF-κB. The present results allow us to surmise that the lj-NF-κB should play a key role in immune response of lamprey, and the function of NF-κB has been maintained during evolution.
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Affiliation(s)
- Peng Su
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Xin Liu
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Yue Pang
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Chang Liu
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Ranran Li
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Qiong Zhang
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Hongfang Liang
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Hao Wang
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China
| | - Qingwei Li
- College of Life Science, Liaoning Normal University, Dalian 116082, China; Lamprey Research Center, Liaoning Normal University, Dalian 116082, China.
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23
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Lecoq L, Raiola L, Chabot PR, Cyr N, Arseneault G, Legault P, Omichinski JG. Structural characterization of interactions between transactivation domain 1 of the p65 subunit of NF-κB and transcription regulatory factors. Nucleic Acids Res 2017; 45:5564-5576. [PMID: 28334776 PMCID: PMC5435986 DOI: 10.1093/nar/gkx146] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 02/25/2017] [Indexed: 01/27/2023] Open
Abstract
p65 is a member of the NF-κB family of transcriptional regulatory proteins that functions as the activating component of the p65-p50 heterodimer. Through its acidic transactivation domain (TAD), p65 has the capacity to form interactions with several different transcriptional regulatory proteins, including TFIIB, TFIIH, CREB-binding protein (CBP)/p300 and TAFII31. Like other acidic TADs, the p65 TAD contains two subdomains (p65TA1 and p65TA2) that interact with different regulatory factors depending on the target gene. Despite its role in controlling numerous NF-κB target genes, there are no high-resolution structures of p65TA1 bound to a target transcriptional regulatory factor. In this work, we characterize the interaction of p65TA1 with two factors, the Tfb1/p62 subunit of TFIIH and the KIX domain of CBP. In these complexes, p65TA1 transitions into a helical conformation that includes its characteristic ΦXXΦΦ motif (Φ = hydrophobic amino acid). Structural and functional studies demonstrate that the two binding interfaces are primarily stabilized by three hydrophobic amino acids within the ΦXXΦΦ motif and these residues are also crucial to its ability to activate transcription. Taken together, the results provide an atomic level description of how p65TA1 is able to bind different transcriptional regulatory factors needed to activate NF-κB target genes.
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Affiliation(s)
- Lauriane Lecoq
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Luca Raiola
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Philippe R Chabot
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Normand Cyr
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Geneviève Arseneault
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Pascale Legault
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - James G Omichinski
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
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24
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Singh AK, Awasthi D, Dubey M, Nagarkoti S, Kumar A, Chandra T, Barthwal MK, Tripathi AK, Dikshit M. High oxidative stress adversely affects NFκB mediated induction of inducible nitric oxide synthase in human neutrophils: Implications in chronic myeloid leukemia. Nitric Oxide 2016; 58:28-41. [PMID: 27264783 DOI: 10.1016/j.niox.2016.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 02/07/2023]
Abstract
Increasing evidence support bimodal action of nitric oxide (NO) both as a promoter and as an impeder of oxygen free radicals in neutrophils (PMNs), however impact of high oxidative stress on NO generation is less explored. In the present study, we comprehensively investigated the effect of high oxidative stress on inducible nitric oxide synthase (iNOS) expression and NO generation in human PMNs. Our findings suggest that PMA or diamide induced oxidative stress in PMNs from healthy volunteers, and high endogenous ROS in PMNs of chronic myeloid leukemia (CML) patients attenuate basal as well as LPS/cytokines induced NO generation and iNOS expression in human PMNs. Mechanistically, we found that under high oxidative stress condition, S-glutathionylation of NFκB (p50 and p65 subunits) severely limits iNOS expression due to its reduced binding to iNOS promoter, which was reversed in presence of DTT. Furthermore, by using pharmacological inhibitors, scavengers and molecular approaches, we identified that enhanced ROS generation via NOX2 and mitochondria, reduced Grx1/2 expression and GSH level associated with NFκB S-glutathionylation in PMNs from CML patients. Altogether data obtained suggest that oxidative status act as an important regulator of NO generation/iNOS expression, and under enhanced oxidative stress condition, NOX2-mtROS-NFκB S-glutathionylation is a feed forward loop, which attenuate NO generation and iNOS expression in human PMNs.
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Affiliation(s)
| | - Deepika Awasthi
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Megha Dubey
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Sheela Nagarkoti
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Ashutosh Kumar
- Department of Pathology, King George's Medical University, Lucknow, India
| | - Tulika Chandra
- Department of Transfusion Medicine, King George's Medical University, Lucknow, India
| | | | - Anil Kumar Tripathi
- Department of Clinical Haematology & Medical Oncology, King George's Medical University, Lucknow, India
| | - Madhu Dikshit
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India.
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25
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Abstract
Genetic switches based on the [Formula: see text] system are master regulators of an array of cellular responses. Recent kinetic experiments have shown that [Formula: see text] can actively remove NF-κB bound to its genetic sites via a process called "molecular stripping." This allows the [Formula: see text] switch to function under kinetic control rather than the thermodynamic control contemplated in the traditional models of gene switches. Using molecular dynamics simulations of coarse-grained predictive energy landscape models for the constituent proteins by themselves and interacting with the DNA we explore the functional motions of the transcription factor [Formula: see text] and its various binary and ternary complexes with DNA and the inhibitor IκB. These studies show that the function of the [Formula: see text] genetic switch is realized via an allosteric mechanism. Molecular stripping occurs through the activation of a domain twist mode by the binding of [Formula: see text] that occurs through conformational selection. Free energy calculations for DNA binding show that the binding of [Formula: see text] not only results in a significant decrease of the affinity of the transcription factor for the DNA but also kinetically speeds DNA release. Projections of the free energy onto various reaction coordinates reveal the structural details of the stripping pathways.
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26
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Gobec M, Tomašič T, Markovič T, Mlinarič-Raščan I, Dolenc MS, Jakopin Ž. Antioxidant and anti-inflammatory properties of 1,2,4-oxadiazole analogs of resveratrol. Chem Biol Interact 2015; 240:200-7. [PMID: 26335192 DOI: 10.1016/j.cbi.2015.08.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/27/2015] [Accepted: 08/27/2015] [Indexed: 12/17/2022]
Abstract
The chemopreventive properties of resveratrol are ascribed mostly to its antioxidant activity, in particular its scavenging ability for reactive oxygen species (ROS), and to the inhibition of NF-κB pathway which has also been suggested as an important underlying mechanism of its reported properties. In present study, a small library of nine 1,2,4-oxadiazole-based structural analogs of resveratrol were assayed for their antioxidant and anti-inflammatory activities. Several compounds showed significant inhibitory activities against NF-κB and/or ROS production. Compound 2, incorporating two para-hydroxyphenyl moieties connected by the 1,2,4-oxadiazole ring, was the most active, its potency in inhibiting activation of NF-κB and ROS scavenging abilities surpassing that of resveratrol. Additionally, we elucidated the mechanisms underlying the NF-κB inhibitory activity of compound 2. Finally, in contrast to resveratrol, compound 2 significantly reduced the LPS-induced release of pro-inflammatory cytokines, indicating its prominent anti-inflammatory potential.
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Affiliation(s)
- Martina Gobec
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI-1000 Ljubljana, Slovenia
| | - Tihomir Tomašič
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI-1000 Ljubljana, Slovenia
| | - Tijana Markovič
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI-1000 Ljubljana, Slovenia
| | - Irena Mlinarič-Raščan
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI-1000 Ljubljana, Slovenia
| | - Marija Sollner Dolenc
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI-1000 Ljubljana, Slovenia
| | - Žiga Jakopin
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI-1000 Ljubljana, Slovenia.
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27
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Kong LM, Deng X, Zuo ZL, Sun HD, Zhao QS, Li Y. Identification and validation of p50 as the cellular target of eriocalyxin B. Oncotarget 2015; 5:11354-64. [PMID: 25404639 PMCID: PMC4294364 DOI: 10.18632/oncotarget.2461] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 09/12/2014] [Indexed: 12/27/2022] Open
Abstract
As an ent-kaurene diterpenoid isolated from Isodon eriocalyx var. Laxiflora, Eriocalyxin B (EriB) possesses potent bioactivity of antitumor and anti-autoimmune inflammation, which has been suggested to work through inhibition of NF-kappaB (NF-κB) signaling. However, the direct target of EriB remains elusive. In this study, we showed that EriB induced apoptosis is associated with the inhibition of NF-κB signaling in SMMC-7721 hepatocellular carcinoma cells. With activity-based probe profiling, we identified p50 protein as the direct target of EriB. We showed that cysteine 62 is the critical residue of p50 for EriB binding through the α, β-unsaturated ketones. As the result, EriB selectively blocks the binding between p50 and the response elements, whereas having no effect on the dimerization or the nuclear translocation of p50 and p65. SiRNA mediated knockdown of p50 attenuated the apoptosis induced by EriB in SMMC-7721 cells. Taken together, our studies illustrated that EriB induces cancer cell apoptosis through interfering with the binding between NF-κB and the response elements by targeting the cysteine 62 of p50, which highlights its potential for the development of p50 targeted cancer therapeutic agents.
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Affiliation(s)
- Ling-Mei Kong
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China. Graduate University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Xu Deng
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Zhi-Li Zuo
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Han-Dong Sun
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Qin-Shi Zhao
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Yan Li
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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28
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Nguyen VS, Loh XY, Wijaya H, Wang J, Lin Q, Lam Y, Wong WSF, Mok YK. Specificity and inhibitory mechanism of andrographolide and its analogues as antiasthma agents on NF-κB p50. JOURNAL OF NATURAL PRODUCTS 2015; 78:208-217. [PMID: 25615020 DOI: 10.1021/np5007179] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Andrographolide (1) is a diterpenoid lactone with an α,β-unsaturated lactone group that inhibits NF-κB DNA binding. Andrographolide reacts with the nucleophilic Cys62 of NF-κB p50 through a Michael addition at the Δ(12(13)) exocylic double bond to form a covalent adduct. Using computer docking, site-directed mutagenesis, and mass spectrometry, the noncovalent interactions between andrographolide and additional binding site residues other than Cys62 were found to be essential for the covalent incorporation of andrographolide. Furthermore, the addition reaction of andrographolide on Cys62 was highly dependent on the redox conditions and on the vicinity of nearby, positively charged Arg residues in the conserved RxxRxR motif. The reaction mechanisms of several of the analogues were determined, showing that 14-deoxy-11,12-didehydroandrographolide (8) reacts with NF-κB p50 via a novel mechanism distinct from andrographolide. The noncovalent interaction and redox environment of the binding site should be considered, in addition to the electrophilicity, when designing a covalent drug. Analogues similar in structure appear to use distinct reaction mechanisms and may have very different cytotoxicities, e.g., compound 6.
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Affiliation(s)
- Van Sang Nguyen
- Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
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29
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Oh JE, Kim MS, Jeon WK, Seo YK, Kim BC, Hahn JH, Park CS. A nuclear factor kappa B-derived inhibitor tripeptide inhibits UVB-induced photoaging process. J Dermatol Sci 2014; 76:196-205. [DOI: 10.1016/j.jdermsci.2014.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 09/18/2014] [Accepted: 10/02/2014] [Indexed: 12/11/2022]
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30
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Qanungo S, Uys JD, Manevich Y, Distler AM, Shaner B, Hill EG, Mieyal JJ, Lemasters JJ, Townsend DM, Nieminen AL. N-acetyl-L-cysteine sensitizes pancreatic cancers to gemcitabine by targeting the NFκB pathway. Biomed Pharmacother 2014; 68:855-64. [PMID: 25257100 DOI: 10.1016/j.biopha.2014.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/05/2014] [Indexed: 01/04/2023] Open
Abstract
First-line therapy for pancreatic cancer is gemcitabine. Although tumors may initially respond to the gemcitabine treatment, soon tumor resistance develops leading to treatment failure. Previously, we demonstrated in human MIA PaCa-2 pancreatic cancer cells that N-acetyl-l-cysteine (NAC), a glutathione (GSH) precursor, prevents NFκB activation via S-glutathionylation of p65-NFκB, thereby blunting expression of survival genes. In this study, we documented the molecular sites of S-glutathionylation of p65, and we investigated whether NAC can suppress NFκB signaling and augment a therapeutic response to gemcitabine in vivo. Mass spectrometric analysis of S-glutathionylated p65-NFκB protein in vitro showed post-translational modifications of cysteines 38, 105, 120, 160 and 216 following oxidative and nitrosative stress. Circular dichroism revealed that S-glutathionylation of p65-NFκB did not change secondary structure of the protein, but increased tryptophan fluorescence revealed altered tertiary structure. Gemcitabine and NAC individually were not effective in decreasing MIA PaCa-2 tumor growth in vivo. However, combination treatment with NAC and gemcitabine decreased tumor growth by approximately 50%. NAC treatment also markedly enhanced tumor apoptosis in gemcitabine-treated mice. Compared to untreated tumors, gemcitabine treatment alone increased p65-NFκB nuclear translocation (3.7-fold) and DNA binding (2.5-fold), and these effects were blunted by NAC. In addition, NAC plus gemcitabine treatment decreased anti-apoptotic XIAP protein expression compared to gemcitabine alone. None of the treatments, however, affected extent of tumor hypoxia, as assessed by EF5 staining. Together, these results indicate that adjunct therapy with NAC prevents NFκB activation and improves gemcitabine chemotherapeutic efficacy.
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Affiliation(s)
- Suparna Qanungo
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston 29425, SC, USA; Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, DD505 Drug Discovery Building, 70, President Street, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA
| | - Joachim D Uys
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA
| | - Yefim Manevich
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA
| | - Anne M Distler
- Department of Pharmacology, Case Western Reserve University, Cleveland 44106, OH, USA; Louis Stokes Veterans Affairs Medical Research Center, Cleveland 44106, OH, USA
| | - Brooke Shaner
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, DD505 Drug Discovery Building, 70, President Street, Charleston 29425, SC, USA
| | - Elizabeth G Hill
- Department of Public Health Sciences, Medical University of South Carolina, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA
| | - John J Mieyal
- Department of Pharmacology, Case Western Reserve University, Cleveland 44106, OH, USA; Louis Stokes Veterans Affairs Medical Research Center, Cleveland 44106, OH, USA
| | - John J Lemasters
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston 29425, SC, USA; Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, DD505 Drug Discovery Building, 70, President Street, Charleston 29425, SC, USA; Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA
| | - Danyelle M Townsend
- Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, DD505 Drug Discovery Building, 70, President Street, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA
| | - Anna-Liisa Nieminen
- Center for Cell Death, Injury & Regeneration, Medical University of South Carolina, Charleston 29425, SC, USA; Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, DD505 Drug Discovery Building, 70, President Street, Charleston 29425, SC, USA; Hollings Cancer Center, Medical University of South Carolina, Charleston 29425, SC, USA.
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31
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Turco MM, Sousa MC. The structure and specificity of the type III secretion system effector NleC suggest a DNA mimicry mechanism of substrate recognition. Biochemistry 2014; 53:5131-9. [PMID: 25040221 PMCID: PMC4131895 DOI: 10.1021/bi500593e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Many pathogenic bacteria utilize
the type III secretion system
(T3SS) to translocate effector proteins directly into host cells,
facilitating colonization. In enterohemmorhagic Escherichia
coli (EHEC), a subset of T3SS effectors is essential for
suppression of the inflammatory response in hosts, including humans.
Identified as a zinc protease that cleaves NF-κB transcription
factors, NleC is one such effector. Here, we investigate NleC substrate
specificity, showing that four residues around the cleavage site in
the DNA-binding loop of the NF-κB subunit RelA strongly influence
the cleavage rate. Class I NF-κB subunit p50 is cleaved at a
reduced rate consistent with conservation of only three of these four
residues. However, peptides containing 10 residues on each side of
the scissile bond were not efficiently cleaved by NleC, indicating
that elements distal from the cleavage site are also important for
substrate recognition. We present the crystal structure of NleC and
show that it mimics DNA structurally and electrostatically. Consistent
with this model, mutation of phosphate-mimicking residues in NleC
reduces the level of RelA cleavage. We propose that global recognition
of NF-κB subunits by DNA mimicry combined with a high sequence
selectivity for the cleavage site results in exquisite NleC substrate
specificity. The structure also shows that despite undetectable similarity
of its sequence to those of other Zn2+ proteases beyond
its conserved HExxH Zn2+-binding motif, NleC is a member
of the Zincin protease superfamily, albeit divergent from its structural
homologues. In particular, NleC displays a modified Ψ-loop motif
that may be important for folding and refolding requirements implicit
in T3SS translocation.
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Affiliation(s)
- Michelle Marian Turco
- Department of Chemistry and Biochemistry, University of Colorado at Boulder , Boulder, Colorado 80309-0596, United States
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32
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Tiwari M, Mikuni S, Muto H, Kinjo M. Determination of dissociation constant of the NFκB p50/p65 heterodimer using fluorescence cross-correlation spectroscopy in the living cell. Biochem Biophys Res Commun 2013; 436:430-5. [PMID: 23751347 DOI: 10.1016/j.bbrc.2013.05.121] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/29/2013] [Indexed: 12/29/2022]
Abstract
Two-laser-beam fluorescence cross-correlation spectroscopy (FCCS) is promising technique that provides quantitative information about the interactions of biomolecules. The p50/p65 heterodimer is the most abundant and well understood of the NFκB dimers in most cells. However, the quantitative value of affinity, namely the K(d), for the heterodimer in living cells is not known yet. To quantify the heterodimerization of the IPT domain of p50/p65 in the living cell, we used two-laser-beam FCCS. The K(d) values of mCherry2- and EGFP-fused p50 and p65 were determined to be 0.46 μM in the cytoplasm and 1.06 μM in the nucleus of the living cell. These results suggest the different binding affinities of the p50/p65 heterodimer in the cytoplasm and nucleus of the living cell and different complex formation in each region.
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Affiliation(s)
- Manisha Tiwari
- Laboratory of Molecular Cell Dynamics, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan
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33
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Xu W, Xue L, Sun Y, Henry A, Battle JM, Micault M, Morris SW. Bcl10 is an essential regulator for A20 gene expression. J Physiol Biochem 2013; 69:821-34. [DOI: 10.1007/s13105-013-0259-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 04/29/2013] [Indexed: 01/22/2023]
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34
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Crawley CD, Raleigh DR, Kang S, Voce DJ, Schmitt AM, Weichselbaum RR, Yamini B. DNA damage-induced cytotoxicity is mediated by the cooperative interaction of phospho-NF-κB p50 and a single nucleotide in the κB-site. Nucleic Acids Res 2012. [PMID: 23180782 PMCID: PMC3553961 DOI: 10.1093/nar/gks1120] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Phosphorylation of the NF-κB subunit, p50, is necessary for cytotoxicity in response to DNA methylation damage. Here, we demonstrate that serine 329 phosphorylation regulates the interaction of p50 with specific NF-κB binding elements based on the identity of a single κB-site nucleotide. Specifically, S329 phosphorylation reduces the affinity of p50 for κB-sites that have a cytosine (C) at the -1 position without affecting binding to sequences with a -1 adenine. The differential interaction between phospho-p50 and the -1 base regulates the downstream transcriptional response and underlies the inhibition of anti-apoptotic gene expression following DNA damage. In genes with multiple κB-sites, the presence of a single -1C κB-site enables inhibition of NF-κB-dependent activity. The data suggest that interaction between phospho-p50 and the -1 κB nucleotide facilitates cytotoxicity in response to DNA damage. Moreover, although conservation of the entire κB-site sequence is not seen across species, the identity of the -1 nt in critical anti-apoptotic genes is conserved such that the overall response to DNA damage is maintained.
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Affiliation(s)
- Clayton D Crawley
- Section of Neurosurgery, Department of Surgery, The University of Chicago, Chicago, IL 60637, USA
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35
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Bartlett NW, Slater L, Glanville N, Haas JJ, Caramori G, Casolari P, Clarke DL, Message SD, Aniscenko J, Kebadze T, Zhu J, Mallia P, Mizgerd JP, Belvisi M, Papi A, Kotenko SV, Johnston SL, Edwards MR. Defining critical roles for NF-κB p65 and type I interferon in innate immunity to rhinovirus. EMBO Mol Med 2012; 4:1244-60. [PMID: 23165884 PMCID: PMC3531601 DOI: 10.1002/emmm.201201650] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/19/2012] [Accepted: 09/20/2012] [Indexed: 12/24/2022] Open
Abstract
The importance of NF-κB activation and deficient anti-viral interferon induction in the pathogenesis of rhinovirus-induced asthma exacerbations is poorly understood. We provide the first in vivo evidence in man and mouse that rhinovirus infection enhanced bronchial epithelial cell NF-κB p65 nuclear expression, NF-κB p65 DNA binding in lung tissue and NF-κB-regulated airway inflammation. In vitro inhibition of NF-κB reduced rhinovirus-induced pro-inflammatory cytokines but did not affect type I/III interferon induction. Rhinovirus-infected p65-deficient mice exhibited reduced neutrophilic inflammation, yet interferon induction, antiviral responses and virus loads were unaffected, indicating that NF-κB p65 is required for pro-inflammatory responses, but redundant in interferon induction by rhinoviruses in vivo. Conversely, IFNAR1−/− mice exhibited enhanced neutrophilic inflammation with impaired antiviral immunity and increased rhinovirus replication, demonstrating that interferon signalling was critical to antiviral immunity. We thus provide new mechanistic insights into rhinovirus infection and demonstrate the therapeutic potential of targeting NF-κB p65 (to suppress inflammation but preserve anti-viral immunity) and type I IFN signalling (to enhance deficient anti-viral immunity) to treat rhinovirus-induced exacerbations of airway diseases.
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Affiliation(s)
- Nathan W Bartlett
- Department of Respiratory Medicine, National Heart Lung Institute, Imperial College London, London, UK
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36
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Bogdanov AA, Metelev V, Zhang S, Kumar ATN. Sensing of transcription factor binding via cyanine dye pair fluorescence lifetime changes. MOLECULAR BIOSYSTEMS 2012; 8:2166-73. [PMID: 22710322 DOI: 10.1039/c2mb25057h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We designed and synthesized sensors for imaging transcription factor-DNA interactions using a complementary pair of 21-base pair long oligonucleotides (ODNs) carrying two internucleoside phosphate-linked cyanine fluorophores that can either engage in Förster's resonance energy transfer (FRET) with fluorescence emission or assemble into a ground state quenched dimer with short fluorescence lifetimes (FL). Cyanine fluorophores were linked to ODNs within the NF-κB binding site. These sensors were tested in the presence of recombinant p50 and p65 NF-κB proteins or constitutively NF-κB activating HeLa cell lysates. By using a coherent light excitation source we followed changes in fluorescence lifetime of the donor (Cy5.5) at the donor's excitation and emission light wavelengths, as well as the acceptor (800CW or Cy7 cyanine fluorophores) in FRET mode. We observed increases in the donor lifetime in both emitting (0.08-0.15 ns) and non-emitting quenched (0.21 ns) sensors in response to protein binding. The measurements of lifetimes in FRET mode in quenched pair-carrying ODN duplex sensors showed significant differences in FL of the acceptor cyanine fluorophore between NF-κB-containing and NF-κB-free samples but not in control sensors with ODN sequences that have decreased binding affinity to NF-κB. We anticipate that the observed effects will be instrumental for developing sensors enabling non-invasive imaging in cells that undergo activation of NF-κB.
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Affiliation(s)
- Alexei A Bogdanov
- The Laboratory of Molecular Imaging Probes S6-434, Department of Radiology, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA.
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37
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Abstract
The signaling module that specifies nuclear factor-κΒ (NF-κB) activation is a three-component system: NF-κB, inhibitor of NF-κΒ (IκΒ), and IκΒ kinase complex (IKK). IKK receives upstream signals from the surface or inside the cell and converts itself into a catalytically active form, leading to the destruction of IκB in the inhibited IκB:NF-κB complex, leaving active NF-κB free to regulate target genes. Hidden within this simple module are family members that all can undergo various modifications resulting in expansion of functional spectrum. Three-dimensional structures representing all three components are now available. These structures have allowed us to interpret cellular observations in molecular terms and at the same time helped us to bring forward new concepts focused towards understanding the specificity in the NF-κB activation pathway.
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Affiliation(s)
- Gourisankar Ghosh
- Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, CA 92903, USA.
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38
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Manuvakhova MS, Johnson GG, White MC, Ananthan S, Sosa M, Maddox C, McKellip S, Rasmussen L, Wennerberg K, Hobrath JV, White EL, Maddry JA, Grimaldi M. Identification of novel small molecule activators of nuclear factor-κB with neuroprotective action via high-throughput screening. J Neurosci Res 2011; 89:58-72. [PMID: 21046675 DOI: 10.1002/jnr.22526] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Neuronal noncytokine-dependent p50/p65 nuclear factor-κB (the primary NF-κB complex in the brain) activation has been shown to exert neuroprotective actions. Thus neuronal activation of NF-κB could represent a viable neuroprotective target. We have developed a cell-based assay able to detect NF-κB expression enhancement, and through its use we have identified small molecules able to up-regulate NF-κB expression and hence trigger its activation in neurons. We have successfully screened approximately 300,000 compounds and identified 1,647 active compounds. Cluster analysis of the structures within the hit population yielded 14 enriched chemical scaffolds. One high-potency and chemically attractive representative of each of these 14 scaffolds and four singleton structures were selected for follow-up. The experiments described here highlighted that seven compounds caused noncanonical long-lasting NF-κB activation in primary astrocytes. Molecular NF-κB docking experiments indicate that compounds could be modulating NF-κB-induced NF-κB expression via enhancement of NF-κB binding to its own promoter. Prototype compounds increased p65 expression in neurons and caused its nuclear translocation without affecting the inhibitor of NF-κB (I-κB). One of the prototypical compounds caused a large reduction of glutamate-induced neuronal death. In conclusion, we have provided evidence that we can use small molecules to activate p65 NF-κB expression in neurons in a cytokine receptor-independent manner, which results in both long-lasting p65 NF-κB translocation/activation and decreased glutamate neurotoxicity.
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Affiliation(s)
- Marina S Manuvakhova
- Laboratory of Neuropharmacology, Department of Biochemistry and Molecular Biology, Drug Discovery Division, Southern Research Institute, Birmingham, Alabama 35205, USA
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Pan Y, Nussinov R. The role of response elements organization in transcription factor selectivity: the IFN-β enhanceosome example. PLoS Comput Biol 2011; 7:e1002077. [PMID: 21698143 PMCID: PMC3116919 DOI: 10.1371/journal.pcbi.1002077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 04/19/2011] [Indexed: 12/04/2022] Open
Abstract
What is the mechanism through which transcription factors (TFs) assemble specifically along the enhancer DNA? The IFN-β enhanceosome provides a good model system: it is small; its components' crystal structures are available; and there are biochemical and cellular data. In the IFN-β enhanceosome, there are few protein-protein interactions even though consecutive DNA response elements (REs) overlap. Our molecular dynamics (MD) simulations on different motif combinations from the enhanceosome illustrate that cooperativity is achieved via unique organization of the REs: specific binding of one TF can enhance the binding of another TF to a neighboring RE and restrict others, through overlap of REs; the order of the REs can determine which complexes will form; and the alternation of consensus and non-consensus REs can regulate binding specificity by optimizing the interactions among partners. Our observations offer an explanation of how specificity and cooperativity can be attained despite the limited interactions between neighboring TFs on the enhancer DNA. To date, when addressing selective TF binding, attention has largely focused on RE sequences. Yet, the order of the REs on the DNA and the length of the spacers between them can be a key factor in specific combinatorial assembly of the TFs on the enhancer and thus in function. Our results emphasize cooperativity via RE binding sites organization.
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Affiliation(s)
- Yongping Pan
- Basic Science Program, SAIC-Frederick, Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, Maryland, United States of America
| | - Ruth Nussinov
- Basic Science Program, SAIC-Frederick, Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, Maryland, United States of America
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Huxford T, Ghosh G. A structural guide to proteins of the NF-kappaB signaling module. Cold Spring Harb Perspect Biol 2010; 1:a000075. [PMID: 20066103 DOI: 10.1101/cshperspect.a000075] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The prosurvival transcription factor NF-kappaB specifically binds promoter DNA to activate target gene expression. NF-kappaB is regulated through interactions with IkappaB inhibitor proteins. Active proteolysis of these IkappaB proteins is, in turn, under the control of the IkappaB kinase complex (IKK). Together, these three molecules form the NF-kappaB signaling module. Studies aimed at characterizing the molecular mechanisms of NF-kappaB, IkappaB, and IKK in terms of their three-dimensional structures have lead to a greater understanding of this vital transcription factor system.
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Affiliation(s)
- Tom Huxford
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA
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41
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Levita J, Nawawi A, Mutalib A, Ibrahim S. Andrographolide: A Review of its Anti-inflammatory Activity via Inhibition of NF-kappaB Activation from Computational Chemistry Aspects. INT J PHARMACOL 2010. [DOI: 10.3923/ijp.2010.569.576] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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42
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Crinelli R, Carloni E, Menotta M, Giacomini E, Bianchi M, Ambrosi G, Giorgi L, Magnani M. Oxidized ultrashort nanotubes as carbon scaffolds for the construction of cell-penetrating NF-kappaB decoy molecules. ACS NANO 2010; 4:2791-2803. [PMID: 20411956 DOI: 10.1021/nn100057c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Oligonucleotide (ODN) decoys are synthetic ODNs containing the DNA binding sequence of a transcription factor. When delivered to cells, these molecules can compete with endogenous sequences for binding the transcription factor, thus inhibiting its ability to activate the expression of target genes. Modulation of gene expression by decoy ODNs against nuclear factor-kappaB (NF-kappaB), a transcription factor regulating many genes involved in immunity, has been achieved in a variety of immune/inflammatory disorders. However, the successful use of transcription factor decoys depends on an efficient means to bring the synthetic DNA to target cells. It is known that single-walled carbon nanotubes (SWCNTs), under certain conditions, are able to cross the cell membrane. Thus, we have evaluated the possibility to functionalize SWCNTs with decoy ODNs against NF-kappaB in order to improve their intracellular delivery. To couple ODNs to CNTs, we have exploited the carbodiimide chemistry which allows covalent binding of amino-modified ODNs to carboxyl groups introduced onto SWCNTs through oxidation. The effective binding of ODNs to nanotubes has been demonstrated by a combination of microscopic, spectroscopic, and electrophoretic techniques. The uptake and subcellular distribution of ODN decoys bound to SWCNTs was analyzed by fluorescence microscopy. ODNs were internalized into macrophages and accumulated in the cytosol. Moreover, no cytotoxicity associated with SWCNT administration was observed. Finally, NF-kappaB-dependent gene expression was significantly reduced in cells receiving nanomolar concentrations of SWCNT-NF-kappaB decoys compared to cells receiving SWCNTs or SWCNTs functionalized with a nonspecific ODN sequence, demonstrating both efficacy and specificity of the approach.
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Affiliation(s)
- Rita Crinelli
- Department of Biomolecular Sciences, Biochemistry and Molecular Biology Section, University of Urbino Carlo Bo, 61029 Urbino, PU, Italy.
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43
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Huxford T, Hoffmann A, Ghosh G. Understanding the logic of IκB:NF-κB regulation in structural terms. Curr Top Microbiol Immunol 2010; 349:1-24. [PMID: 20845107 DOI: 10.1007/82_2010_99] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
NF-κB is an inducible transcription factor that controls expression of diverse stress response genes. The entire mammalian NF-κB family is generated from a small cadre of five gene products that assemble with one another in various combinations to form active homo- and heterodimers. The ability of NF-κB to alter target gene expression is regulated at many levels. Chief among these regulatory mechanisms is the noncovalent association in the cell cytoplasm of NF-κB dimers with IκB inhibitor proteins. Removal of IκB leads to accumulation of active NF-κB within the cell nucleus where it binds to specific DNA sequences contained within the promoter regions of target genes and initiates recruitment of general transcription factors and assembly of the basal transcription machinery. Here we provide a detailed description of these fundamental NF-κB regulatory events using as a basis macromolecular structures and experimental data derived from structure-based biochemistry.
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Affiliation(s)
- Tom Huxford
- Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1030, USA
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44
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Kinetic enhancement of NF-kappaBxDNA dissociation by IkappaBalpha. Proc Natl Acad Sci U S A 2009; 106:19328-33. [PMID: 19887633 DOI: 10.1073/pnas.0908797106] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A hallmark of the NF-kappaB transcription response to inflammatory cytokines is the remarkably rapid rate of robust activation and subsequent signal repression. Although the rapidity of postinduction repression is explained partly by the fact that the gene for IkappaBalpha is strongly induced by NF-kappaB, the newly synthesized IkappaBalpha still must enter the nucleus and compete for binding to NF-kappaB with the very large number of kappaB sites in the DNA. We present results from real-time binding kinetic experiments, demonstrating that IkappaBalpha increases the dissociation rate of NF-kappaB from the DNA in a highly efficient kinetic process. Analysis of various IkappaB mutant proteins shows that this process requires the C-terminal PEST sequence and the weakly folded fifth and sixth ankyrin repeats of IkappaBalpha. Mutational stabilization of these repeats reduces the efficiency with which IkappaBalpha enhances the dissociation rate.
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45
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Tsai KC, Teng LW, Shao YM, Chen YC, Lee YC, Li M, Hsiao NW. The first pharmacophore model for potent NF-κB inhibitors. Bioorg Med Chem Lett 2009; 19:5665-9. [DOI: 10.1016/j.bmcl.2009.08.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 08/04/2009] [Accepted: 08/05/2009] [Indexed: 11/28/2022]
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46
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Mohapatra DK, Das PP, Sai Reddy D, Yadav J. First total syntheses and absolute configuration of rugulactone and 6(R)-(4′-oxopent-2′-enyl)-5,6-dihydro-2H-pyran-2-one. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.08.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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47
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Structural basis of HIV-1 activation by NF-kappaB--a higher-order complex of p50:RelA bound to the HIV-1 LTR. J Mol Biol 2009; 393:98-112. [PMID: 19683540 DOI: 10.1016/j.jmb.2009.08.023] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 08/04/2009] [Accepted: 08/05/2009] [Indexed: 12/22/2022]
Abstract
The activation and latency of human immunodeficiency virus type 1 (HIV-1) are tightly controlled by the transcriptional activity of its long terminal repeat (LTR) region. The LTR is regulated by viral proteins as well as host factors, including the nuclear factor kappaB (NF-kappaB) that becomes activated in virus-infected cells. The two tandem NF-kappaB sites of the LTR are among the most highly conserved sequence elements of the HIV-1 genome. Puzzlingly, these sites are arranged in a manner that seems to preclude simultaneous binding of both sites by NF-kappaB, although previous biochemical work suggests otherwise. Here, we have determined the crystal structure of p50:RelA bound to the tandem kappaB element of the HIV-1 LTR as a dimeric dimer, providing direct structural evidence that NF-kappaB can occupy both sites simultaneously. The two p50:RelA dimers bind the adjacent kappaB sites and interact through a protein contact that is accommodated by DNA bending. The two dimers clamp DNA from opposite faces of the double helix and form a topological trap of the bound DNA. Consistent with these structural features, our biochemical analyses indicate that p50:RelA binds the HIV-1 LTR tandem kappaB sites with an apparent anti-cooperativity but enhanced kinetic stability. The slow on and off rates we observe may be relevant to viral latency because viral activation requires sustained NF-kappaB activation. Furthermore, our work demonstrates that the specific arrangement of the two kappaB sites on the HIV-1 LTR can modulate the assembly kinetics of the higher-order NF-kappaB complex on the viral promoter. This phenomenon is unlikely restricted to the HIV-1 LTR but probably represents a general mechanism for the function of composite DNA elements in transcription.
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48
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Sinquett FL, Dryer RL, Marcelli V, Batheja A, Covey LR. Single nucleotide changes in the human Igamma1 and Igamma4 promoters underlie different transcriptional responses to CD40. THE JOURNAL OF IMMUNOLOGY 2009; 182:2185-93. [PMID: 19201872 DOI: 10.4049/jimmunol.0802700] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Analysis of subclass-specific germline transcription in activated peripheral B cells revealed a highly biased expression pattern of the four Igamma transcripts to signals through CD40 and IL-4. This difference was most pronounced when comparing the profile of Igamma1 and Igamma4 transcripts and was not expected given the very high degree of sequence conservation between promoters. In this report, the influence of sequence differences on the regulation of the Igamma1 and Igamma4 promoters has been investigated given the highly muted transcriptional activity of the Igamma4 promoter. Two regions were analyzed where single nucleotide differences corresponded to major changes in transcriptional activity. These regions were the previously defined CD40 response region containing three putative NF-kappaB-binding sites and the downstream 36-bp region containing CREB/activating transcription factor and kappaB6 sites. Mutation of a single nucleotide at position 6 within the Igamma4 kappaB6 site increased promoter activity to approximately 50% of the activity of the Igamma1 promoter. Furthermore, elevated promoter strength corresponded with increased binding of p50, p65, c-Rel, RelB, and p300 proteins to a level comparable with that of Igamma1. Minor nucleotide changes to both the Igamma4 CD40 response region and the 36-bp element resulted in a response undistinguishable from an Igamma1 response, suggesting cooperation between the two regulatory regions for optimal transcriptional activity. Collectively, these mutational analyses suggest that minor sequence differences contribute to the composition and affinity of transcriptional protein complexes regulating subclass-specific germline transcription, which in part impacts the overall level of class switch recombination to targeted C(H) regions.
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Affiliation(s)
- Frank L Sinquett
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08854, USA
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49
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Dragan A, Carrillo R, Gerasimova T, Privalov P. Assembling the Human IFN-β Enhanceosome in Solution. J Mol Biol 2008; 384:335-48. [DOI: 10.1016/j.jmb.2008.09.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 07/28/2008] [Accepted: 09/02/2008] [Indexed: 10/21/2022]
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50
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Qian L, Shen Y, Chen JC, Wang YX, Wu XT, Chen TJ, Zheng KC. 3D-QSAR and Docking Studies of Quinazoline Derivatives with the Inhibitory Activity Toward NF-κB. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/qsar.200710132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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