scholarly journals Tumor Necrosis Factor Alpha Inhibits Type I Collagen Synthesis through Repressive CCAAT/Enhancer-Binding Proteins

2000 ◽  
Vol 20 (3) ◽  
pp. 912-918 ◽  
Author(s):  
Patricia Greenwel ◽  
Shizuko Tanaka ◽  
Dmitri Penkov ◽  
Wen Zhang ◽  
Michelle Olive ◽  
...  

ABSTRACT Extracellular matrix (ECM) formation and remodeling are critical processes for proper morphogenesis, organogenesis, and tissue repair. The proinflammatory cytokine tumor necrosis factor alpha (TNF-α) inhibits ECM accumulation by stimulating the expression of matrix proteolytic enzymes and by downregulating the deposition of structural macromolecules such as type I collagen. Stimulation of ECM degradation has been linked to prolonged activation of jun gene expression by the cytokine. Here we demonstrate that TNF-α inhibits transcription of the gene coding for the α2 chain of type I collagen [α2(I) collagen] in cultured fibroblasts by stimulating the synthesis and binding of repressive CCAAT/enhancer proteins (C/EBPs) to a previously identified TNF-α-responsive element. This conclusion was based on the concomitant identification of C/EBPβ and C/EBPδ as TNF-α-induced factors by biochemical purification and expression library screening. It was further supported by the ability of the C/EBP-specific dominant-negative (DN) protein to block TNF-α inhibition of α2(I) collagen but not TNF-α stimulation of the MMP-13 protease. The DN protein also blocked TNF-α downregulation of the gene coding for the α1 chain of type I collagen. The study therefore implicates repressive C/EBPs in the TNF-α-induced signaling pathway that controls ECM formation and remodeling.

2003 ◽  
Vol 23 (2) ◽  
pp. 526-533 ◽  
Author(s):  
Robert Barthel ◽  
Alla V. Tsytsykova ◽  
Amy K. Barczak ◽  
Eunice Y. Tsai ◽  
Christopher C. Dascher ◽  
...  

ABSTRACT Tumor necrosis factor alpha (TNF-α) plays an important role in host containment of infection by Mycobacterium tuberculosis, one of the leading causes of death by an infectious agent globally. Using the pathogenic M. tuberculosis strain H37Rv, we present evidence that upon stimulation of monocytic cells by M. tuberculosis a unique TNF-α enhanceosome is formed, and it is distinct from the TNF-α enhanceosome that forms in T cells stimulated by antigen engagement or virus infection. A distinct set of activators including ATF-2, c-jun, Ets, Sp1, Egr-1 and the coactivator proteins CBP/p300 are recruited to the TNF-α promoter after stimulation with M. tuberculosis. Furthermore, the formation of this enhanceosome is dependent on inducer-specific helical phasing relationships between transcription factor binding sites. We also show that the transcriptional activity of CBP/p300 is potentiated by mycobacterial stimulation of monocytes. The identification of TNF-α regulatory elements and coactivators involved in M. tuberculosis-stimulated gene expression thus provides potential selective molecular targets in the modulation of TNF-α gene expression in the setting of mycobacterial infection.


2004 ◽  
Vol 24 (21) ◽  
pp. 9317-9326 ◽  
Author(s):  
Hyung-Joo Kwon ◽  
Erin Haag Breese ◽  
Eva Vig-Varga ◽  
Yong Luo ◽  
Younghee Lee ◽  
...  

ABSTRACT A myriad of stimuli including proinflammatory cytokines, viruses, and chemical and mechanical insults activate a kinase complex composed of IκB kinase β (IKK-β), IKK-α, and IKK-γ/N, leading to changes in NF-κB-dependent gene expression. However, it is not clear how the NF-κB response is tailored to specific cellular insults. Signaling molecule that interacts with mouse pelle-like kinase (SIMPL) is a signaling component required for tumor necrosis factor alpha (TNF-α)-dependent but not interleukin-1-dependent NF-κB activation. Herein we demonstrate that nuclear localization of SIMPL is required for type I TNF receptor-induced NF-κB activity. SIMPL interacts with nuclear p65 in a TNF-α-dependent manner to promote endogenous NF-κB-dependent gene expression. The interaction between SIMPL and p65 enhances p65 transactivation activity. These data support a model in which TNF-α activation of NF-κB dependent-gene expression requires nuclear relocalization of p65 as well as nuclear relocalization of SIMPL, generating a TNF-α-specific induction of gene expression.


2001 ◽  
Vol 69 (5) ◽  
pp. 2964-2971 ◽  
Author(s):  
Albert Sabirov ◽  
Satoru Kodama ◽  
Takashi Hirano ◽  
Masashi Suzuki ◽  
Goro Mogi

ABSTRACT Nontypeable Haemophilus influenzae (NTHi) is a major pathogen causing otitis media (OM). One of the outer membrane proteins of NTHi, P6, is a common antigen to all strains and is considered a candidate for mucosal vaccine. We have previously reported that intranasal immunization with P6 and cholera toxin (CT) could induce P6-specific immunoglobulin A (IgA) antibodies in the middle ear. In the present study, we assessed the effect of intranasal immunization for the protection against NTHi-induced OM. Mice were immunized intranasally with P6 and CT as an adjuvant on days 0, 7, and 14. Control mice were given phosphate-buffered saline (PBS) without antigen. One week after the final immunization, a suspension of live NTHi (107 CFU) was injected into the tympanic cavity to induce experimental OM. On days 3 and 7 after bacterial challenge, mice were killed and middle ear effusions (MEEs) were collected. All immunized mice showed elevated titers of P6-specific antibodies in MEEs. The rank order of specific antibody included, from highest to lowest levels, IgG, IgA, and IgM. In addition, immunized mice showed enhanced clearance of NTHi from the middle ear and the number of NTHi in MEEs of immunized mice was reduced by 97% on day 3 and by 92% on day 7 after bacterial challenge relative the number in the MEEs of control mice. The protective effect of intranasal immunization on the incidence of NTHi-induced experimental OM was evident on day 7 after challenge. By day 7, the number of MEEs in immunized mice was 64% less than that in control mice and the incidence of NTHi culture-positive MEEs in immunized mice was 56% less than that in control mice. Less stimulation of tumor necrosis factor alpha (TNF-α) production in the middle ear was evident on day 3 after challenge. Immunized mice showed lower concentrations of TNF-α in MEEs. These results indicate that intranasal immunization affords protection against experimental OM as evidenced by enhanced clearance of NTHi and less stimulation of TNF-α production in the middle ear. These findings suggest that a nasal vaccine might be useful for preventing OM.


2020 ◽  
Author(s):  
Wenna Gao ◽  
Ruilin Zhu ◽  
liu yang

Background: Mounting evidence has suggested tumor necrosis factor-alpha (TNF-α) can promote the development of diabetic retinopathy (DR), and TNF-α gene variants may influence DR risk. However, the results are quite different. Objectives: To comprehensively address this issue, we performed the meta-analysis to evaluate the association of TNF-α-308 G/A and -238 G/A polymorphism with DR. Method: Data were retrieved in a systematic manner and analyzed using STATA Statistical Software. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Allelic and genotypic comparisons between cases and controls were evaluated. Results: For the TNF-α-308 G/A polymorphism, overall analysis suggested a marginal association with DR [the OR(95%CI) of (GA versus GG), (GA + AA) versus GG, and (A versus G) are 1.21(1.04, 1.41), 1.20(1.03, 1.39), and 1.14(1.01, 1.30), respectively]. And the subgroup analysis indicated an enhanced association among the European population. For the TNF-α-238 G/A polymorphism, there was mild correlation in the entire group [the OR(95%CI) of (GA versus GG) is 1.55(1.14,2.11) ], which was strengthened among the Asian population. Conclusion: The meta-analysis suggested that -308 A and -238 A allele in TNF-α gene potentially increased DR risk and showed a discrepancy in different ethnicities.


2005 ◽  
Vol 60 (4) ◽  
pp. 471-475 ◽  
Author(s):  
Barbara Orzeszko ◽  
Tomasz Świtaj ◽  
Anna B. Jakubowska-Mućka ◽  
Witold Lasek ◽  
Andrzej Orzeszko ◽  
...  

Certain adamantylated heterocycles were previously shown to enhance the secretion of tumor necrosis factor alpha (TNF-α) by murine melanoma cells that have been transduced with the gene for human TNF-α and constitutively expressed this cytokine. The stimulatory potency of those compounds depended, among other factors, on the structure of the linker between the adamantyl residue and the heterocyclic core. In the present study, a series of (1-adamantyl)alkylsulfanyl derivatives of heterocyclic compounds was prepared by alkylation of the corresponding thioheterocyles. Of the novel adamantylalkylthio compounds tested in the aforementioned cell line, 2-(2-adamantan-1-ylethylsulfanyl)- 4-methyl-pyrimidine was found to be the most active


2013 ◽  
Vol 87 (23) ◽  
pp. 12935-12948 ◽  
Author(s):  
Jie Zhang ◽  
Kezhen Wang ◽  
Shuai Wang ◽  
Chunfu Zheng

NF-κB plays central roles in regulation of diverse biological processes, including innate and adaptive immunity and inflammation. HSV-1 is the archetypal member of the alphaherpesviruses, with a large genome encoding over 80 viral proteins, many of which are involved in virus-host interactions and show immune modulatory capabilities. In this study, we demonstrated that the HSV-1 ICP0 protein, a viral E3 ubiquitin ligase, was shown to significantly suppress tumor necrosis factor alpha (TNF-α)-mediated NF-κB activation. ICP0 was demonstrated to bind to the NF-κB subunits p65 and p50 by coimmunoprecipitation analysis. ICP0 bound to the Rel homology domain (RHD) of p65. Fluorescence microscopy demonstrated that ICP0 abolished nuclear translocation of p65 upon TNF-α stimulation. Also, ICP0 degraded p50 via its E3 ubiquitin ligase activity. The RING finger (RF) domain mutant ICP0 (ICP0-RF) lost its ability to inhibit TNF-α-mediated NF-κB activation and p65 nuclear translocation and degrade p50. Notably, the RF domain of ICP0 was sufficient to interact with p50 and abolish NF-κB reporter gene activity. Here, it is for the first time shown that HSV-1 ICP0 interacts with p65 and p50, degrades p50 through the ubiquitin-proteasome pathway, and prevents NF-κB-dependent gene expression, which may contribute to immune evasion and pathogenesis of HSV-1.


2016 ◽  
Vol 36 (9) ◽  
pp. 1342-1353 ◽  
Author(s):  
Gil Diamant ◽  
Tal Eisenbaum ◽  
Dena Leshkowitz ◽  
Rivka Dikstein

The proinflammatory cytokine tumor necrosis factor alpha (TNF-α) modulates the expression of many genes, primarily through activation of NF-κB. Here, we examined the global effects of the elongation factor Spt5 on nascent and mature mRNAs of TNF-α-induced cells using chromatin and cytosolic subcellular fractions. We identified several classes of TNF-α-induced genes controlled at the level of transcription, splicing, and chromatin retention. Spt5 was found to facilitate splicing and chromatin release in genes displaying high induction rates. Further analysis revealed striking effects of TNF-α on the splicing of 25% of expressed genes; the vast majority were not transcriptionally induced. Splicing enhancement of noninduced genes by TNF-α was transient and independent of NF-κB. Investigating the underlying basis, we found that Spt5 is required for the splicing facilitation of the noninduced genes. In line with this, Spt5 interacts with Sm core protein splicing factors. Furthermore, following TNF-α treatment, levels of RNA polymerase II (Pol II) but not Spt5 are reduced from the splicing-induced genes, suggesting that these genes become enriched with a Pol II-Spt5 form. Our findings revealed the Pol II-Spt5 complex as a highly competent coordinator of cotranscriptional splicing.


2006 ◽  
Vol 26 (24) ◽  
pp. 9244-9255 ◽  
Author(s):  
Xiaolan Feng ◽  
Shirin Bonni ◽  
Karl Riabowol

ABSTRACT ING proteins affect apoptosis, growth, and DNA repair by transducing stress signals such as DNA damage, binding histones, and subsequently regulating chromatin structure and p53 activity. p53 target genes, including the p21 cyclin-dependent kinase inhibitor and Bax, an inducer of apoptosis, are regulated by ING proteins. To identify additional targets downstream of p33ING1 and p32ING2, cDNA microarrays were performed on phenotypically normal human primary fibroblasts. The 0.36% of genes affected by ING proteins in primary fibroblasts were distinct from targets seen in established cells and included the HSP70 heat shock gene, whose promoter was specifically induced >10-fold. ING1-induced expression of HSP70 shifted cells from survival to a death pathway in response to tumor necrosis factor alpha (TNF-α), and p33ING1b protein showed synergy with TNF-α in inducing apoptosis, which correlated with reduced NF-κB-dependent transcription. These findings are consistent with previous reports that HSP70 promotes TNF-α-mediated apoptosis by binding I-κΒ kinase gamma and impairing NF-κB survival signaling. Induction of HSP70 required the amino terminus of ING1b but not the plant homeodomain region that was recently identified as a histone binding domain. Regulation of HSP70 gene expression by the ING tumor suppressors provides a novel link between the INGs and the stress-regulated NF-κB survival pathway important in hypoxia and angiogenesis.


2008 ◽  
Vol 82 (16) ◽  
pp. 7790-7798 ◽  
Author(s):  
Marlynne Q. Nicol ◽  
Jean-Marie Mathys ◽  
Albertina Pereira ◽  
Kevin Ollington ◽  
Michael H. Ieong ◽  
...  

ABSTRACT Human immunodeficiency virus (HIV)-positive persons are predisposed to pulmonary infections, even after receiving effective highly active antiretroviral therapy. The reasons for this are unclear but may involve changes in innate immune function. HIV type 1 infection of macrophages impairs effector functions, including cytokine production. We observed decreased constitutive tumor necrosis factor alpha (TNF-α) concentrations and increased soluble tumor necrosis factor receptor type II (sTNFRII) in bronchoalveolar lavage fluid samples from HIV-positive subjects compared to healthy controls. Moreover, net proinflammatory TNF-α activity, as measured by the TNF-α/sTNFRII ratio, decreased as HIV-related disease progressed, as manifested by decreasing CD4 cell count and increasing HIV RNA (viral load). Since TNF-α is an important component of the innate immune system and is produced upon activation of Toll-like receptor (TLR) pathways, we hypothesized that the mechanism associated with deficient TNF-α production in the lung involved altered TLR expression or a deficit in the TLR signaling cascade. We found decreased Toll-like receptor 1 (TLR1) and TLR4 surface expression in HIV-infected U1 monocytic cells compared to the uninfected parental U937 cell line and decreased TLR message in alveolar macrophages (AMs) from HIV-positive subjects. In addition, stimulation with TLR1/2 ligand (Pam3Cys) or TLR4 ligand (lipopolysaccharide) resulted in decreased intracellular phosphorylated extracellular signal-regulated kinase and subsequent decreased transcription and expression of TNF-α in U1 cells compared to U937 cells. AMs from HIV-positive subjects also showed decreased TNF-α production in response to these TLR2 and TLR4 ligands. We postulate that HIV infection alters expression of TLRs with subsequent changes in mitogen-activated protein kinase signaling and cytokine production that ultimately leads to deficiencies of innate immune responses that predispose HIV-positive subjects to infection.


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