scholarly journals Human Cytomegalovirus Attenuates Interleukin-1β and Tumor Necrosis Factor Alpha Proinflammatory Signaling by Inhibition of NF-κB Activation

2006 ◽  
Vol 80 (11) ◽  
pp. 5588-5598 ◽  
Author(s):  
Michael A. Jarvis ◽  
Jamie A. Borton ◽  
Amy M. Keech ◽  
John Wong ◽  
William J. Britt ◽  
...  

ABSTRACT Viral infection is associated with a vigorous inflammatory response characterized by cellular infiltration and release of the proinflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-α). In the present study, we identified a novel function of human cytomegalovirus (HCMV) that results in inhibition of IL-1 and TNF-α signaling pathways. The effect on these pathways was limited to cells infected with the virus, occurred at late times of infection, and was independent of cell type or virus strain. IL-1 and TNF-α signaling pathways converge at a point upstream of NF-κB activation and involve phosphorylation and degradation of the NF-κB inhibitory molecule IκBα. The HCMV inhibition of IL-1 and TNF-α pathways corresponded to a suppression of NF-κB activation. Analysis of IκBα phosphorylation and degradation suggested that HCMV induced two independent blocks in NF-κB activation, which occurred upstream from the point of convergence of the IL-1 and TNF-α pathways. We believe that the ability of HCMV to inhibit these two major proinflammatory pathways reveals a critical aspect of HCMV biology, with possible importance for immune evasion, as well as establishment of infection in cell types persistently infected by this virus.

2002 ◽  
Vol 76 (11) ◽  
pp. 5515-5521 ◽  
Author(s):  
Joshua M. Friedman ◽  
Marshall S. Horwitz

ABSTRACT Recombinant adenoviruses (Ads) are useful tools in gene transfer because they are able to infect a wide variety of tissues and cell types and do not require a replicating target cell. However, transgene expression is only transient due to host innate and acquired immune responses to the virus. Most recombinant Ads have deletions of early region 3 (E3) genes, allowing more space for insertion of the transgene. Although the E3 region is not necessary for infection, it has been observed that these “nonessential” genes have immunomodulatory properties. We demonstrate here that the E3 region of Ad inhibits the activation of NF-κB induced by tumor necrosis factor alpha (TNF-α) and interleukin-1. Ad E3 is able to prevent NF-κB from entering the nucleus, where it is normally active. Ad E3 also appears to function by preventing the activation of the kinase complex, IKK, which is responsible for phosphorylation of IκB that retains NF-κB in the cytoplasm in an inactive state. The prevention of NF-κB activation has been mapped to a complex of two of the seven E3 products, E3-10.4K and E3-14.5K (RIDα/β). These and other studies indicate that, by using Ad vectors containing the E3 region, it may be possible to reduce the harmful proinflammatory effects of TNF-α and other cytokines that compromise the use of Ad gene therapy vectors in vivo.


1999 ◽  
Vol 67 (12) ◽  
pp. 6473-6477 ◽  
Author(s):  
Liping Zhang ◽  
Tracey A. Ignatowski ◽  
Robert N. Spengler ◽  
Bernice Noble ◽  
Murray W. Stinson

ABSTRACT The histone-like protein (HlpA) is highly conserved among streptococci. After lysis of streptococci in infected tissues, HlpA can enter the bloodstream and bind to proteoglycans in the glomerular capillaries of kidneys, where it can react with antibodies or stimulate host cell receptors. Deposits of streptococcal antigens in tissues have been associated with localized acute inflammation. In this study, we measured the ability of purified HlpA (5 to 100 μg/ml), fromStreptococcus mitis, to induce the production of proinflammatory cytokines by cultured, murine peritoneal macrophages. The release of tumor necrosis factor alpha (TNF-α) and interleukin-1 (IL-1) was time and concentration dependent and was not diminished by the presence of polymyxin B. Exposure of macrophages to a mixture of HlpA and lipoteichoic acid resulted in a synergistic response in the production of both TNF-α and IL-1. Stimulation with a mixture of HlpA and heparin resulted in reduced cytokine production (50% less IL-1 and 76% less TNF-α) compared to that by cells incubated with HlpA alone. The inclusion of antibodies specific to HlpA in macrophage cultures during stimulation with HlpA did not affect the quantity of TNF-α or IL-1 produced. These observations suggest that streptococcal histone may contribute to tissue injury at infection sites by promoting monocytes/macrophages to synthesize and release cytokines that initiate and exacerbate inflammation. Streptococcus pyogenes, which can infect tissues in enormous numbers, may release sufficient amounts of HlpA to reach the kidneys and cause acute poststreptococcal glomerulonephritis.


1999 ◽  
Vol 67 (3) ◽  
pp. 1455-1460 ◽  
Author(s):  
Yael Yuhas ◽  
Lester Shulman ◽  
Abraham Weizman ◽  
Elizabeth Kaminsky ◽  
Alexey Vanichkin ◽  
...  

ABSTRACT Neurologic manifestations, mainly convulsions, are the most frequent extraintestinal complications of shigellosis. We used an animal model to study the roles of tumor necrosis factor alpha (TNF-α) and interleukin-1 β (IL-1β) inShigella-related seizures. Administration of Shigella dysenteriae 60R sonicate enhanced the sensitivity of mice to the proconvulsant pentylenetetrazole (PTZ) within 7 h. This was indicated by a significantly higher mean convulsion score and an increased number of mice responding with clonic-tonic seizures in theShigella-pretreated group. Preinjection of mice with anti-murine TNF-α (anti-mTNF-α) or anti-murine IL-1β (anti-mIL-1β) 30 min prior to administration of Shigellasonicate abolished their enhanced response to PTZ at 7 h. Mean convulsion scores were reduced by anti-mTNF-α from 1.2 to 0.8 (P = 0.017) and by anti-mIL-1β from 1.3 to 0.7 (P = 0.008). Preinjection of anti-mTNF-α also reduced the percentage of mice responding with clonic-tonic seizures, from 48 to 29% (P = 0.002), and preinjection of anti-mIL-1β reduced it from 53 to 21% (P = 0.012). Neutralization of TNF-α or IL-1β did not protect the mice from death due to S. dysenteriae 60R. These findings indicate that TNF-α and IL-1β play a role in the very early sensitization of the central nervous system to convulsive activity after S. dysenteriae administration. Similar mechanisms may trigger neurologic disturbances in other infectious diseases.


2006 ◽  
Vol 80 (23) ◽  
pp. 11686-11698 ◽  
Author(s):  
Christina Montag ◽  
Jutta Wagner ◽  
Iris Gruska ◽  
Christian Hagemeier

ABSTRACT NF-κB plays an important role in the early cellular response to pathogens by activating genes involved in inflammation, immune response, and cell proliferation and survival. NF-κB is also utilized by many viral pathogens, like human cytomegalovirus (HCMV), to activate their own gene expression programs, reflecting intricate roles for NF-κB in both antiviral defense mechanisms and viral physiology. Here we show that the NF-κB signaling pathway stimulated by proinflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β) becomes inhibited in HCMV-infected cells. The block to NF-κB signaling is first noticeable during the early phase of infection but is fully established only at later times. Biochemical and genetic evidence demonstrates that the viral inhibition of proinflammatory signaling by distinct cytokines occurs upstream of the convergence point of NF-κB-activating pathways, i.e., the IκB kinase complex, and that it is mediated via different mechanisms. Consistent with this, we further show that an HCMV variant that has lost the ability to downregulate TNF-α-induced NF-κB signaling also fails to downregulate surface expression of TNF receptor 1, thereby mechanistically linking the inhibition of TNF-α-induced NF-κB signaling by HCMV to TNF receptor targeting. Our data support a model whereby HCMV inhibits cytokine-induced NF-κB signaling at later times during infection, and we suggest that this contributes to the inhibition of the cell's antiviral defense program.


Diabetes ◽  
1993 ◽  
Vol 42 (7) ◽  
pp. 1026-1031 ◽  
Author(s):  
K. Yamada ◽  
N. Takane ◽  
S. Otabe ◽  
C. Inada ◽  
M. Inoue ◽  
...  

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.


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