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Rabies virus infection induces type I interferon production in an IPS-1 dependent manner while dendritic cell activation relies on IFNAR signaling.

Faul EJ, Wanjalla CN, Suthar MS, Gale M, Wirblich C, Schnell MJ - PLoS Pathog. (2010)

Bottom Line: However, IPS-1 is essential for both BMDC activation and IFN production.In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection.However, only RIG-I-/- cells exhibit a delay in type I IFN production.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.

ABSTRACT
As with many viruses, rabies virus (RABV) infection induces type I interferon (IFN) production within the infected host cells. However, RABV has evolved mechanisms by which to inhibit IFN production in order to sustain infection. Here we show that RABV infection of dendritic cells (DC) induces potent type I IFN production and DC activation. Although DCs are infected by RABV, the viral replication is highly suppressed in DCs, rendering the infection non-productive. We exploited this finding in bone marrow derived DCs (BMDC) in order to differentiate which pattern recognition receptor(s) (PRR) is responsible for inducing type I IFN following infection with RABV. Our results indicate that BMDC activation and type I IFN production following a RABV infection is independent of TLR signaling. However, IPS-1 is essential for both BMDC activation and IFN production. Interestingly, we see that the BMDC activation is primarily due to signaling through the IFNAR and only marginally induced by the initial infection. To further identify the receptor recognizing RABV infection, we next analyzed BMDC from Mda-5-/- and RIG-I-/- mice. In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection. However, only RIG-I-/- cells exhibit a delay in type I IFN production. In order to determine the role that IPS-1 plays in vivo, we infected mice with pathogenic RABV. We see that IPS-1-/- mice are more susceptible to infection than IPS-1+/+ mice and have a significantly increased incident of limb paralysis.

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DC activation following a RABV infection occurs independent of TLR signaling.BMDC derived from TLR-3−/− mice (A and C) or MyD88−/− mice (B and D). (A–B) CD86 upregulation following RABV infection of BMDCs was monitored at 12, 24, and 48 hours post infection. One representative knock-out and wildtype mouse is shown at 12hpi. (C–D) For each sample the fold increase in activation was determined by dividing the geometric mean fluorescent intensity (MFI) of the sample by the MFI of the uninfected sample. (C) Data is from two independent experiments and each point is representative of BMDC from one mouse. (D) Data is from four independent experiments and each point is representative of BMDC from two pooled mice. Statistical significance was determined by T-test analysis and any significance is indicated, ***p<0.001.
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ppat-1001016-g004: DC activation following a RABV infection occurs independent of TLR signaling.BMDC derived from TLR-3−/− mice (A and C) or MyD88−/− mice (B and D). (A–B) CD86 upregulation following RABV infection of BMDCs was monitored at 12, 24, and 48 hours post infection. One representative knock-out and wildtype mouse is shown at 12hpi. (C–D) For each sample the fold increase in activation was determined by dividing the geometric mean fluorescent intensity (MFI) of the sample by the MFI of the uninfected sample. (C) Data is from two independent experiments and each point is representative of BMDC from one mouse. (D) Data is from four independent experiments and each point is representative of BMDC from two pooled mice. Statistical significance was determined by T-test analysis and any significance is indicated, ***p<0.001.

Mentions: First, we analyzed the role that TLR signaling plays in BMDC activation and type I IFN production following a RABV infection. It has been previously reported that following infection of human postmitotic neurons with RABV, there is an increased production of IFN-ß and TLR-3 mRNAs. In addition, treatment of neurons with poly(I:C), a TLR-3 agonist, generated a similar cytokine profile to that which was seen following RABV infection [25]. Thus, we differentiated BMDCs from TLR-3−/− and congenic wildtype mice and infected the cells with RABV. We then analyzed the infected cells for the presence of CD86 (Figure 4A). As shown in Figure 4C, there is no significant difference in the expression of CD86 on the cell surface of RABV infected BMDCs derived from TLR-3−/− or wildtype mice. As expected, TLR ligands that signal via other TLR receptors, namely TLR-4 (LPS), TLR-9 (ODN1826), and TLR-7/8 (R848), equally activate BMDCs derived from wildtype (wt) or TLR-3−/− mice. Interestingly, poly(I:C), a known ligand for TLR-3, was able to activate BMDC isolated from TLR-3−/− mice as well as wt mice. However, it has been previously shown that poly(I:C) can also signal through Mda-5 and that Mda-5 is the dominant receptor for mediating type I IFN induction following poly(I:C) stimulation in BMDCs [33], [34]. As the RLR pathway remains intact in TLR-3−/− mice, BMDC activation in TLR-3−/− cells following poly(I:C) stimulation is not inexplicable, but rather highlights the need for a better TLR-3 agonist. Taken as a whole and based on the fact that that RABV infection activated BMDC derived from both wt and TLR-3−/− mice equally, we conclude that TLR-3 signaling is not required for the activation of BMDCs following a RABV infection.


Rabies virus infection induces type I interferon production in an IPS-1 dependent manner while dendritic cell activation relies on IFNAR signaling.

Faul EJ, Wanjalla CN, Suthar MS, Gale M, Wirblich C, Schnell MJ - PLoS Pathog. (2010)

DC activation following a RABV infection occurs independent of TLR signaling.BMDC derived from TLR-3−/− mice (A and C) or MyD88−/− mice (B and D). (A–B) CD86 upregulation following RABV infection of BMDCs was monitored at 12, 24, and 48 hours post infection. One representative knock-out and wildtype mouse is shown at 12hpi. (C–D) For each sample the fold increase in activation was determined by dividing the geometric mean fluorescent intensity (MFI) of the sample by the MFI of the uninfected sample. (C) Data is from two independent experiments and each point is representative of BMDC from one mouse. (D) Data is from four independent experiments and each point is representative of BMDC from two pooled mice. Statistical significance was determined by T-test analysis and any significance is indicated, ***p<0.001.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2908622&req=5

ppat-1001016-g004: DC activation following a RABV infection occurs independent of TLR signaling.BMDC derived from TLR-3−/− mice (A and C) or MyD88−/− mice (B and D). (A–B) CD86 upregulation following RABV infection of BMDCs was monitored at 12, 24, and 48 hours post infection. One representative knock-out and wildtype mouse is shown at 12hpi. (C–D) For each sample the fold increase in activation was determined by dividing the geometric mean fluorescent intensity (MFI) of the sample by the MFI of the uninfected sample. (C) Data is from two independent experiments and each point is representative of BMDC from one mouse. (D) Data is from four independent experiments and each point is representative of BMDC from two pooled mice. Statistical significance was determined by T-test analysis and any significance is indicated, ***p<0.001.
Mentions: First, we analyzed the role that TLR signaling plays in BMDC activation and type I IFN production following a RABV infection. It has been previously reported that following infection of human postmitotic neurons with RABV, there is an increased production of IFN-ß and TLR-3 mRNAs. In addition, treatment of neurons with poly(I:C), a TLR-3 agonist, generated a similar cytokine profile to that which was seen following RABV infection [25]. Thus, we differentiated BMDCs from TLR-3−/− and congenic wildtype mice and infected the cells with RABV. We then analyzed the infected cells for the presence of CD86 (Figure 4A). As shown in Figure 4C, there is no significant difference in the expression of CD86 on the cell surface of RABV infected BMDCs derived from TLR-3−/− or wildtype mice. As expected, TLR ligands that signal via other TLR receptors, namely TLR-4 (LPS), TLR-9 (ODN1826), and TLR-7/8 (R848), equally activate BMDCs derived from wildtype (wt) or TLR-3−/− mice. Interestingly, poly(I:C), a known ligand for TLR-3, was able to activate BMDC isolated from TLR-3−/− mice as well as wt mice. However, it has been previously shown that poly(I:C) can also signal through Mda-5 and that Mda-5 is the dominant receptor for mediating type I IFN induction following poly(I:C) stimulation in BMDCs [33], [34]. As the RLR pathway remains intact in TLR-3−/− mice, BMDC activation in TLR-3−/− cells following poly(I:C) stimulation is not inexplicable, but rather highlights the need for a better TLR-3 agonist. Taken as a whole and based on the fact that that RABV infection activated BMDC derived from both wt and TLR-3−/− mice equally, we conclude that TLR-3 signaling is not required for the activation of BMDCs following a RABV infection.

Bottom Line: However, IPS-1 is essential for both BMDC activation and IFN production.In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection.However, only RIG-I-/- cells exhibit a delay in type I IFN production.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.

ABSTRACT
As with many viruses, rabies virus (RABV) infection induces type I interferon (IFN) production within the infected host cells. However, RABV has evolved mechanisms by which to inhibit IFN production in order to sustain infection. Here we show that RABV infection of dendritic cells (DC) induces potent type I IFN production and DC activation. Although DCs are infected by RABV, the viral replication is highly suppressed in DCs, rendering the infection non-productive. We exploited this finding in bone marrow derived DCs (BMDC) in order to differentiate which pattern recognition receptor(s) (PRR) is responsible for inducing type I IFN following infection with RABV. Our results indicate that BMDC activation and type I IFN production following a RABV infection is independent of TLR signaling. However, IPS-1 is essential for both BMDC activation and IFN production. Interestingly, we see that the BMDC activation is primarily due to signaling through the IFNAR and only marginally induced by the initial infection. To further identify the receptor recognizing RABV infection, we next analyzed BMDC from Mda-5-/- and RIG-I-/- mice. In the absence of either receptor, there is a significant decrease in BMDC activation at 12h post infection. However, only RIG-I-/- cells exhibit a delay in type I IFN production. In order to determine the role that IPS-1 plays in vivo, we infected mice with pathogenic RABV. We see that IPS-1-/- mice are more susceptible to infection than IPS-1+/+ mice and have a significantly increased incident of limb paralysis.

Show MeSH
Related in: MedlinePlus