scholarly journals Cytokine-Independent Upregulation of MDA5 in Viral Infection

2007 ◽  
Vol 81 (13) ◽  
pp. 7316-7319 ◽  
Author(s):  
Jacob S. Yount ◽  
Thomas M. Moran ◽  
Carolina B. López
Keyword(s):  
Virus Infection ◽  
Sendai Virus ◽  
Virus Detection ◽  
Type I ◽  
Type I Ifn ◽  
Rna Helicases ◽  
Necrosis Factor Alpha ◽  
Maximal Sensitivity ◽  
Factor Alpha ◽  
Necrosis Factor

ABSTRACT The RNA helicases RIG-I and MDA5 detect virus infection of dendritic cells (DCs) leading to cytokine induction. Maximal sensitivity for virus detection by these helicases is obtained after their upregulation, which is thought to occur primarily through type I interferon (IFN) signaling. Here we demonstrate that in response to paramyxovirus infection, RIG-I upregulation requires type I IFN whereas MDA5 expression is increased by Sendai virus infection independently of signaling mediated by type I IFN, STAT1, tumor necrosis factor alpha, or NF-κB. This MDA5 upregulation is largely lost in IRF3 knockout DCs and is achieved in type I IFN-deficient cells expressing constitutively active IRF3.

scholarly journals Selective Interferon Responses of Intestinal Epithelial Cells Minimize Tumor Necrosis Factor Alpha Cytotoxicity

2020 ◽  
Vol 94 (21) ◽  
Author(s):  
Jacob A. Van Winkle ◽  
David A. Constant ◽  
Lena Li ◽  
Timothy J. Nice
Keyword(s):  
Specific Response ◽  
Type I ◽  
Intestinal Epithelial ◽  
Type I Ifn ◽  
Necrosis Factor Alpha ◽  
Type Iii ◽  
Factor Alpha ◽  
Type Iii Ifn ◽  
Necrosis Factor

ABSTRACT Interferon (IFN) family cytokines stimulate genes (interferon-stimulated genes [ISGs]) that are integral to antiviral host defense. Type I IFNs act systemically, whereas type III IFNs act preferentially at epithelial barriers. Among barrier cells, intestinal epithelial cells (IECs) are particularly dependent on type III IFN for the control and clearance of virus infection, but the physiological basis of this selective IFN response is not well understood. Here, we confirm that type III IFN treatment elicits robust and uniform ISG expression in neonatal mouse IECs and inhibits the replication of IEC-tropic rotavirus. In contrast, type I IFN elicits a marginal ISG response in neonatal mouse IECs and does not inhibit rotavirus replication. In vitro treatment of IEC organoids with type III IFN results in ISG expression that mirrors the in vivo type III IFN response. However, IEC organoids have increased expression of the type I IFN receptor relative to neonate IECs, and the response of IEC organoids to type I IFN is strikingly increased in magnitude and scope relative to type III IFN. The expanded type I IFN-specific response includes proapoptotic genes and potentiates toxicity triggered by tumor necrosis factor alpha (TNF-α). The ISGs stimulated in common by type I and III IFNs have strong interferon-stimulated response element (ISRE) promoter motifs, whereas the expanded set of type I IFN-specific ISGs, including proapoptotic genes, have weak ISRE motifs. Thus, the preferential responsiveness of IECs to type III IFN in vivo enables selective ISG expression during infection that confers antiviral protection but minimizes disruption of intestinal homeostasis. IMPORTANCE Enteric viral infections are a major cause of gastroenteritis worldwide and have the potential to trigger or exacerbate intestinal inflammatory diseases. Prior studies have identified specialized innate immune responses that are active in the intestinal epithelium following viral infection, but our understanding of the benefits of such an epithelium-specific response is incomplete. Here, we show that the intestinal epithelial antiviral response is programmed to enable protection while minimizing epithelial cytotoxicity that can often accompany an inflammatory response. Our findings offer new insight into the benefits of a tailored innate immune response at the intestinal barrier and suggest how dysregulation of this response could promote inflammatory disease.

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 ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis ◽  
Type I Collagen ◽  
Type I ◽  
Necrosis Factor Alpha ◽  
Gene Coding ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Stimulation Of

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.

scholarly journals Constitutive production of interleukin-6 and tumor necrosis factor- alpha from spontaneously proliferating T cells in patients with human T- cell lymphotropic virus type-I/II

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 571-574 ◽  
Author(s):  
RB Lal ◽  
DL Rudolph
Keyword(s):  
Tumor Necrosis Factor ◽  
Tumor Necrosis Factor Alpha ◽  
Tumor Necrosis ◽  
Tnf Alpha ◽  
Type I ◽  
Necrosis Factor Alpha ◽  
Human T Cell ◽  
Factor Alpha ◽  
Culture Supernatants ◽  
Necrosis Factor

Abstract The human T-cell lymphotropic viruses (HTLV) type I and type II are capable of inducing a variety of cellular genes, including many of the cytokines that regulate cell proliferation. To determine if the spontaneous proliferation of peripheral blood mononuclear cells from patients infected with HTLV-I and HTLV-II was related to coordinate expression of cytokines, we analyzed the levels of interleukin-1 beta (IL-1 beta), IL-2, IL-3, IL-4, IL-6, tumor necrosis factor-alpha (TNF- alpha) and interferon-tau (IFN-tau) in culture supernatants derived from spontaneously proliferating cells. Significantly elevated levels of IL-6 and TNF-alpha were present in culture supernatants from HTLV- I/II-infected individuals when compared with normal controls (P less than .01). Kinetic experiments showed that both IL-6 and TNF-alpha were elevated by day 5. None of the other cytokines (IL-1 beta, IL-2, IL-3, IL-4, and IFN-tau) were detectable in any of the culture. These data suggest that release of IL-6 and TNF-alpha may regulate lymphocyte proliferation in HTLV-I/II-infected individuals.

scholarly journals Tula hantavirus infection of Vero E6 cells induces apoptosis involving caspase 8 activation

2004 ◽  
Vol 85 (11) ◽  
pp. 3261-3268 ◽  
Author(s):  
Xiao-Dong Li ◽  
Sami Kukkonen ◽  
Olli Vapalahti ◽  
Alexander Plyusnin ◽  
Hilkka Lankinen ◽  
...  
Keyword(s):  
Influenza A ◽  
Time Course ◽  
Caspase 3 ◽  
Hantavirus Infection ◽  
Caspase 8 ◽  
Type I ◽  
Tnf Receptor ◽  
Necrosis Factor Alpha ◽  
Factor Alpha ◽  
Necrosis Factor

Hantaviruses are known to cause two severe human diseases: haemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. The mechanisms of pathogenesis of these two diseases are progressively becoming understood. Recently, two hantaviruses, Hantaan and Prospect Hill were reported to cause programmed cell death of Vero E6 cells. This study shows that Tula hantavirus (TULV) infection efficiently triggers an apoptotic programme in infected Vero E6 cells, and that the replication of TULV is required for the activation of caspase 3 and the cleavage of poly (ADP-ribose) polymerase, two molecular hallmarks of apoptosis. The enforced treatment of infected Vero E6 cells with tumour necrosis factor alpha (TNF-α), but not interferon alpha (IFN-α), advanced the time course of apoptosis. Furthermore, caspase 8 was activated on day 4 post-infection, the same day when caspase 3 was activated. TNF receptor 1 was induced during a late stage of TULV infection. These data suggest that, unlike during influenza A virus infection, TNF-α, but not type I IFN-α/β, may contribute significantly to apoptosis in a synergistic manner with TULV propagation. Interestingly, pretreatment with a broad-spectrum caspase inhibitor, z-VAD-fmk, efficiently inhibited apoptosis of TULV-infected Vero E6 cells. Taken together, these results suggest that TULV replication initiates a typical apoptotic programme involving caspase 8 activation.

scholarly journals Sendai Virus Infection Induces Efficient Adaptive Immunity Independently of Type I Interferons

2006 ◽  
Vol 80 (9) ◽  
pp. 4538-4545 ◽  
Author(s):  
Carolina B. López ◽  
Jacob S. Yount ◽  
Tamar Hermesh ◽  
Thomas M. Moran
Keyword(s):  
T Cells ◽  
Virus Infection ◽  
Adaptive Immunity ◽  
Sendai Virus ◽  
Cytotoxic T Cells ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifn ◽  
Type I Ifns

ABSTRACT Adaptive immunity in response to virus infection involves the generation of Th1 cells, cytotoxic T cells, and antibodies. This type of immune response is crucial for the clearance of virus infection and for long-term protection against reinfection. Type I interferons (IFNs), the primary innate cytokines that control virus growth and spreading, can influence various aspects of adaptive immunity. The development of antiviral immunity depends on many viral and cellular factors, and the extent to which type I IFNs contribute to the generation of adaptive immunity in response to a viral infection is controversial. Using two strains (Cantell and 52) of the murine respiratory Sendai virus (SeV) with differential abilities to induce type I IFN production from infected cells, together with type I IFN receptor-deficient mice, we examined the role of type I IFNs in the generation of adaptive immunity. Our results show that type I IFNs facilitate virus clearance and enhance the migration and maturation of dendritic cells after SeV infection in vivo; however, soon after infection, mice clear the virus from their lungs and efficiently generate cytotoxic T cells independently of type I IFN signaling. Furthermore, animals that are unresponsive to type I IFN develop long-term anti-SeV immunity, including CD8+ T cells and antibodies. Significantly, this memory response is able to protect mice against challenge with a lethal dose of virus. In conclusion, our results show that primary and secondary anti-SeV adaptive immunities are developed normally in the absence of type I IFN responsiveness.

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