scholarly journals Regulation of hypoxia-inducible factor-1α by NF-κB

2008 ◽  
Vol 412 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Patrick van Uden ◽  
Niall S. Kenneth ◽  
Sonia Rocha
Keyword(s):  
Hypoxia Inducible Factor ◽  
Nuclear Factor Κb ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Low Oxygen ◽  
Prolyl Hydroxylases ◽  
Hypoxic Conditions ◽  
Factor Α ◽  
Interfering Rna ◽  
Necrosis Factor

HIF (hypoxia-inducible factor) is the main transcription factor activated by low oxygen tensions. HIF-1α (and other α subunits) is tightly controlled mostly at the protein level, through the concerted action of a class of enzymes called PHDs (prolyl hydroxylases) 1, 2 and 3. Most of the knowledge of HIF derives from studies following hypoxic stress; however, HIF-1α stabilization is also found in non-hypoxic conditions through an unknown mechanism. In the present study, we demonstrate that NF-κB (nuclear factor κB) is a direct modulator of HIF-1α expression. The HIF-1α promoter is responsive to selective NF-κB subunits. siRNA (small interfering RNA) studies for individual NF-κB members revealed differential effects on HIF-1α mRNA levels, indicating that NF-κB can regulate basal HIF-1α expression. Finally, when endogenous NF-κB is induced by TNFα (tumour necrosis factor α) treatment, HIF-1α levels also change in an NF-κB-dependent manner. In conclusion, we find that NF-κB can regulate basal TNFα and, in certain circumstances, the hypoxia-induced HIF-1α.

scholarly journals Hypoxia-inducible Factor Mediates Hypoxic and Tumor Necrosis Factor α-induced Increases in Tumor Necrosis Factor-α Converting Enzyme/ADAM17 Expression by Synovial Cells

2007 ◽  
Vol 282 (46) ◽  
pp. 33714-33724 ◽  
Author(s):  
Martine Charbonneau ◽  
Kelly Harper ◽  
Francine Grondin ◽  
Manuela Pelmus ◽  
Patrick P. McDonald ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Hypoxia Inducible Factor ◽  
Synovial Cells ◽  
Joint Diseases ◽  
Mrna Levels ◽  
Low Oxygen ◽  
Factor Α ◽  
Necrosis Factor

Chronic hypoxia and inflammatory cytokines are hallmarks of inflammatory joint diseases like rheumatoid arthritis (RA), suggesting a link between this microenvironment and central pathological events. Because TACE/ADAM17 is the predominant protease catalyzing the release of tumor necrosis factor α (TNFα), a cytokine that triggers a cascade of events leading to RA, we examined the regulation of this metalloprotease in response to hypoxia and TNFα itself. We report that low oxygen concentrations and TNFα enhance TACE mRNA levels in synovial cells through direct binding of hypoxia-inducible factor-1 (HIF-1) to the 5′ promoter region. This is associated with elevated TACE activity as shown by the increase in TNFα shedding rate. By the use of HIF-1-deficient cells and by obliterating NF-κB activation, it was determined that the hypoxic TACE response is mediated by HIF-1 signaling, whereas the regulation by TNFα also requires NF-κB activation. As a support for the in vivo relevance of the HIF-1 axis for TACE regulation, immunohistological analysis of TACE and HIF-1 expression in RA synovium indicates that TACE is up-regulated in both fibroblast- and macrophage-like synovial cells where it localizes with elevated expression of both HIF-1 and TNFα. These findings suggest a mechanism by which TACE is increased in RA-affected joints. They also provide novel mechanistic clues on the influence of the hypoxic and inflammatory microenvironment on joint diseases.

scholarly journals TWEAK-FN14 signaling induces lysosomal degradation of a cIAP1–TRAF2 complex to sensitize tumor cells to TNFα

2008 ◽  
Vol 182 (1) ◽  
pp. 171-184 ◽  
Author(s):  
James E. Vince ◽  
Diep Chau ◽  
Bernard Callus ◽  
W. Wei-Lynn Wong ◽  
Christine J. Hawkins ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Nuclear Factor Κb ◽  
Dependent Manner ◽  
Lysosomal Degradation ◽  
Synthetic Inhibitor ◽  
Tnf Superfamily ◽  
Physiological Relevance ◽  
Immortalized Cells ◽  
Factor Α ◽  
Necrosis Factor

Synthetic inhibitor of apoptosis (IAP) antagonists induce degradation of IAP proteins such as cellular IAP1 (cIAP1), activate nuclear factor κB (NF-κB) signaling, and sensitize cells to tumor necrosis factor α (TNFα). The physiological relevance of these discoveries to cIAP1 function remains undetermined. We show that upon ligand binding, the TNF superfamily receptor FN14 recruits a cIAP1–Tnf receptor-associated factor 2 (TRAF2) complex. Unlike IAP antagonists that cause rapid proteasomal degradation of cIAP1, signaling by FN14 promotes the lysosomal degradation of cIAP1–TRAF2 in a cIAP1-dependent manner. TNF-like weak inducer of apoptosis (TWEAK)/FN14 signaling nevertheless promotes the same noncanonical NF-κB signaling elicited by IAP antagonists and, in sensitive cells, the same autocrine TNFα-induced death occurs. TWEAK-induced loss of the cIAP1–TRAF2 complex sensitizes immortalized and minimally passaged tumor cells to TNFα-induced death, whereas primary cells remain resistant. Conversely, cIAP1–TRAF2 complex overexpression limits FN14 signaling and protects tumor cells from TWEAK-induced TNFα sensitization. Lysosomal degradation of cIAP1–TRAF2 by TWEAK/FN14 therefore critically alters the balance of life/death signals emanating from TNF-R1 in immortalized cells.

scholarly journals HIF-1α is a negative regulator of interferon regulatory factors: Implications for interferon production by hypoxic monocytes

2021 ◽  
Vol 118 (26) ◽  
pp. e2106017118
Author(s):  
Travis Peng ◽  
Shin-Yi Du ◽  
Myoungsun Son ◽  
Betty Diamond
Keyword(s):  
Inflammatory Cytokines ◽  
Cell Function ◽  
Hypoxia Inducible Factor ◽  
Human Monocyte ◽  
Nuclear Factor Κb ◽  
Negative Regulator ◽  
Type I ◽  
Hypoxic Conditions ◽  
Stressed Cells ◽  
Factor Α

Patients with severe COVID-19 infection exhibit a low level of oxygen in affected tissue and blood. To understand the pathophysiology of COVID-19 infection, it is therefore necessary to understand cell function during hypoxia. We investigated aspects of human monocyte activation under hypoxic conditions. HMGB1 is an alarmin released by stressed cells. Under normoxic conditions, HMGB1 activates interferon regulatory factor (IRF)5 and nuclear factor-κB in monocytes, leading to expression of type I interferon (IFN) and inflammatory cytokines including tumor necrosis factor α, and interleukin 1β, respectively. When hypoxic monocytes are activated by HMGB1, they produce proinflammatory cytokines but fail to produce type I IFN. Hypoxia-inducible factor-1α, induced by hypoxia, functions as a direct transcriptional repressor of IRF5 and IRF3. As hypoxia is a stressor that induces secretion of HMGB1 by epithelial cells, hypoxia establishes a microenvironment that favors monocyte production of inflammatory cytokines but not IFN. These findings have implications for the pathogenesis of COVID-19.

scholarly journals Hypoxia-inducible factor induction by tumour necrosis factor in normoxic cells requires receptor-interacting protein-dependent nuclear factor kappaB activation

2003 ◽  
Vol 370 (3) ◽  
pp. 1011-1017 ◽  
Author(s):  
YunJin JUNG ◽  
Jennifer S. ISAACS ◽  
Sunmin LEE ◽  
Jane TREPEL ◽  
Zheng-gang LIU ◽  
...  
Keyword(s):  
Tumour Necrosis Factor ◽  
Tumour Necrosis ◽  
Hypoxia Inducible Factor ◽  
Nuclear Factor Κb ◽  
Protein Stabilization ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Interacting Protein ◽  
Tnf Α ◽  
Necrosis Factor

Tumour necrosis factor α (TNF-α) binds to its receptor (TNFR1) and activates both death- and inflammation/survival-related signalling pathways. The inflammation and survival-related signalling cascade results in the activation of the transcription factor, nuclear factor κB (NF-κB) and requires recruitment of receptor-interacting protein (RIP) to TNFR1. The indispensable role of RIP in TNF-induced NF-κB activation has been demonstrated in RIP-/- mice and in cell lines derived from such mice. In the present study, we show that the TNF-α-induced accumulation of hypoxia-inducible factor 1α (HIF-1α) protein in normoxic cells is RIP-dependent. Exposing fibroblasts derived from RIP-/- mice to either cobalt or PMA resulted in an equivalent HIF-1α induction to that seen in RIP+/+ fibroblasts. In contrast, RIP-/- cells were unable to induce HIF-1α in response to TNF-α. Further, transient transfection of NIH 3T3 cells with an NF-κB super-repressor plasmid (an inhibitor of NF-κB activation) also prevented HIF-1α induction by TNF-α. Surprisingly, although HIF-1α mRNA levels remained unchanged after induction by TNF, induction of HIF-1α protein by the cytokine was completely blocked by pretreatment with the transcription inhibitors actinomycin D and 5,6-dichlorobenzimidazole riboside. Finally, TNF failed to induce both HIF-1α, made resistant to von Hippel—Lindau (VHL), and wild-type HIF-1α transfected into VHL-/- cells. These results indicate that HIF-1α induction by TNF-α in normoxic cells is mediated by protein stabilization but is nonetheless uniquely dependent on NF-κB-driven transcription. Thus the results describe a novel mechanism of HIF-1α up-regulation and they identify HIF-1α as a unique component of the NF-κB-mediated inflammatory/survival response.

scholarly journals Tumour necrosis factor α induces co-ordinated activation of rat GSH synthetic enzymes via nuclear factor κB and activator protein-1

2005 ◽  
Vol 391 (2) ◽  
pp. 399-408 ◽  
Author(s):  
Heping Yang ◽  
Nathaniel Magilnick ◽  
Xiaopeng Ou ◽  
Shelly C. Lu
Keyword(s):  
Promoter Activity ◽  
Nuclear Factor Κb ◽  
Mrna Levels ◽  
Nuclear Factor ◽  
Activator Protein 1 ◽  
Tumour Necrosis Factor Α ◽  
Synthetic Enzymes ◽  
H4iie Cells ◽  
Factor Α ◽  
Necrosis Factor

GSH synthesis occurs via two enzymatic steps catalysed by GCL [glutamate–cysteine ligase, made up of GCLC (GCL catalytic subunit), and GCLM (GCL modifier subunit)] and GSS (GSH synthetase). Co-ordinated up-regulation of GCL and GSS further enhances GSH synthetic capacity. The present study examined whether TNFα (tumour necrosis factor α) influences the expression of rat GSH synthetic enzymes. To facilitate transcriptional studies of the rat GCLM, we cloned its 1.8 kb 5′-flanking region. TNFα induces the expression and recombinant promoter activities of GCLC, GCLM and GSS in H4IIE cells. TNFα induces NF-κB (nuclear factor κB) and AP-1 (activator protein 1) nuclear-binding activities. Blocking AP-1 with dominant negative c-Jun or NF-κB with IκBSR (IκB super-repressor, where IκB stands for inhibitory κB) lowered basal expression and inhibited the TNFα-mediated increase in mRNA levels of all three genes. While all three genes have multiple AP-1-binding sites, only GCLC has a NF-κB-binding site. Overexpression with p50 or p65 increased c-Jun mRNA levels, c-Jun-dependent promoter activity and the promoter activity of GCLM and GSS. Blocking NF-κB also lowered basal c-Jun expression and blunted the TNFα-mediated increase in c-Jun mRNA levels. TNFα treatment resulted in increased c-Jun and Nrf2 (nuclear factor erythroid 2-related factor 2) nuclear binding to the antioxidant response element of the rat GCLM and if this was prevented, TNFα no longer induced the GCLM promoter activity. In conclusion, both c-Jun and NF-κB are required for basal and TNFα-mediated induction of GSH synthetic enzymes in H4IIE cells. While NF-κB may exert a direct effect on the GCLC promoter, it induces the GCLM and GSS promoters indirectly via c-Jun.

scholarly journals Turnour necrosis factor stimulates endothelin-1 gene expression in cultured bovine endothelial cells

1992 ◽  
Vol 1 (4) ◽  
pp. 263-266 ◽  
Author(s):  
Silvia Orisio ◽  
Marina Morigi ◽  
Carla Zoja ◽  
Norberto Perico ◽  
Giuseppe Remuzzi
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Hypotensive Effect ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Aortic Endothelial Cells ◽  
Endothelin 1 ◽  
Tnf Α ◽  
Factor Α ◽  
Necrosis Factor

We have studied the effect of human recombinant tumour necrosis factor-α (TNF-α) on gene expression and production of endothelin-1 in cultured bovine aortic endothelial cells. TNF-α (10 and 100 ng ml−1) increased in a time dependent manner the preproendothelin-1 mRNA levels in respect to unstimulated endothelial cells. TNF-α induced endothelin-1 gene expression was associated with a parallel increase in the release of the corresponding peptide in the culture medium. These findings suggest that the enhanced synthesis and release of endothelin-1 occurring in conditions of increased generation of TNF, may act as a modulatory factor that counteracts the hypotensive effect and the excessive platelet aggregation and adhesion induced by TNF.

scholarly journals IOP1, a novel hydrogenase-like protein that modulates hypoxia-inducible factor-1α activity

2006 ◽  
Vol 401 (1) ◽  
pp. 341-352 ◽  
Author(s):  
Jianhe Huang ◽  
Daisheng Song ◽  
Adrian Flores ◽  
Quan Zhao ◽  
Sharon M. Mooney ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Hypoxia Inducible Factor ◽  
Cell Types ◽  
Mrna Levels ◽  
Low Oxygen ◽  
Gene Expressions ◽  
Iron Sulfur Cluster ◽  
Α Subunit ◽  
Protein Levels ◽  
Hypoxic Conditions

A central means by which mammalian cells respond to low oxygen tension is through the activation of the transcription factor HIF-1 (hypoxia-inducible factor-1). Under normoxic conditions, HIF-1α (the α subunit of HIF-1) is targeted for rapid degradation by the ubiquitin–proteasome pathway. Under hypoxic conditions, this degradation is inhibited, thereby leading to the stabilization and activation of HIF-1α. Here, we report the identification of IOP1 (iron-only hydrogenase-like protein 1), a protein homologous with enzymes present in anaerobic organisms that contain a distinctive iron–sulfur cluster. IOP1 is present in a broad range of cell types. Knockdown of IOP1 using siRNA (small interfering RNA) in mammalian cells increases protein levels of HIF-1α under both normoxic and hypoxic conditions, and augments hypoxia-induced HRE (hypoxia response element) reporter gene and endogenous HIF-1α target gene expressions. We find that IOP1 knockdown up-regulates HIF-1α mRNA levels, thereby providing a mechanism by which knockdown induces the observed effects. The results collectively provide evidence that IOP1 is a component of the protein network that regulates HIF-1α in mammalian cells.

scholarly journals Decreased Growth of Vhl−/− Fibrosarcomas Is Associated with Elevated Levels of Cyclin Kinase Inhibitors p21 and p27

2005 ◽  
Vol 25 (11) ◽  
pp. 4565-4578 ◽  
Author(s):  
Fiona A. Mack ◽  
Jagruti H. Patel ◽  
Mangatt P. Biju ◽  
Volker H. Haase ◽  
M. Celeste Simon
Keyword(s):  
Cellular Proliferation ◽  
Kinase Inhibitors ◽  
Hypoxia Inducible Factor ◽  
Suppressor Gene ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Tumor Vascularity ◽  
Von Hippel Lindau ◽  
Interfering Rna ◽  
Hif Pathway

ABSTRACT Inactivating mutations within the von Hippel-Lindau (VHL) tumor suppressor gene predispose patients to develop a variety of highly vascularized tumors. pVHL targets α subunits of the heterodimeric transcription factor hypoxia-inducible factor (HIF), a critical regulator of energy metabolism, angiogenesis, hematopoiesis, and oxygen (O2) delivery, for ubiquitin-mediated degradation in an O2-dependent manner. To investigate the role of Vhl in cellular proliferation and tumorigenesis, we utilized mouse embryonic fibroblasts (MEFs), a common tool for analyzing cell cycle regulation, and generated Vhl − / − MEF-derived fibrosarcomas. Surprisingly, growth of both Vhl − / − MEFs and fibrosarcomas was impaired, although tumor vascularity was increased. Decreased proliferation of Vhl − / − MEFs was correlated with an overexpression of cyclin kinase inhibitors (CKIs) p21 and p27. The transcription of p21 and p27 is inhibited by c-Myc; therefore, the induction of CKIs was attributed to the ability of HIF to antagonize c-Myc activity. Indeed, p21 mRNA levels were elevated under normoxia in Vhl − / − MEFs, while c-Myc transcriptional activity was markedly reduced. Gene silencing of HIF-1α by small interfering RNA reduced p21 and p27 protein and mRNA levels in Vhl − / − MEFs. The induction of p21 and p27, mediated by constitutive activation of the HIF pathway, provides a mechanism for the decreased proliferation rates of Vhl − / − MEFs and fibrosarcomas. These results demonstrate that a loss of pVHL can induce growth arrest in certain cells types, which suggests that additional genetic mutations are necessary for VHL-associated tumorigenesis.

scholarly journals Interaction of mitochondrial thioredoxin with glucocorticoid receptor and NF-κB modulates glucocorticoid receptor and NF-κB signalling in HEK-293 cells

2009 ◽  
Vol 422 (3) ◽  
pp. 521-531 ◽  
Author(s):  
Anna-Maria G. Psarra ◽  
Stefan Hermann ◽  
George Panayotou ◽  
Giannis Spyrou
Keyword(s):  
Transcription Factors ◽  
Glucocorticoid Receptor ◽  
Nuclear Factor Κb ◽  
Reduced Form ◽  
Mrna Levels ◽  
Cytochrome Oxidase Subunit ◽  
Hek 293 ◽  
293 Cells ◽  
Factor Α ◽  
Necrosis Factor

Trx2 (mitochondrial thioredoxin) is an antioxidant and anti-apoptotic factor essential for cell viability. Trx1 (cytoplasmic thioredoxin) is a co-factor and regulator of redox-sensitive transcription factors such as the GR (glucocorticoid receptor) and NF-κB (nuclear factor κB). Both transcription factors have been detected in mitochondria and a role in mitochondrial transcription regulation and apoptosis has been proposed. In the present study, we show using SPR (surface plasmon resonance) and immunoprecepitation that GR and the p65 subunit of NF-κB are Trx2-interacting proteins. The interaction of Trx2 with GR is independent of the presence of GR ligand and of redox conditions. The p65 subunit of NF-κB can interact with Trx2 in the oxidized, but not the reduced, form. Using HEK (human embryonic kidney)-293 cell lines with increased or decreased expression of Trx2, we show that Trx2 modulates transcription of GR and NF-κB reporter genes. Moreover, Trx2 overexpression modulates the mRNA levels of the COX1 (cytochrome oxidase subunit I) and Cytb (cytochrome b), which are known to be regulated by GR and NF-κB. Increased expression of Trx2 differentially affects the expression of Cytb. The glucocorticoid dexamethasone potentiates the expression of Cytb, whereas TNFα (tumour necrosis factor α) down-regulates it. These results suggest a regulatory role for Trx2 in GR and NF-κB signalling pathways.

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