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Differential expression of Toll-like receptors in dendritic cells of patients with dengue during early and late acute phases of the disease.

Torres S, Hernández JC, Giraldo D, Arboleda M, Rojas M, Smit JM, Urcuqui-Inchima S - PLoS Negl Trop Dis (2013)

Bottom Line: In addition, we found a lower expression of TLR2 in patients with DF compared to DHF.This suggests that the virus can affect the interferon response through this signaling pathway.Changes in TLRs expression could play a central role in DC activation, thereby influencing the innate immune response.

View Article: PubMed Central - PubMed

Affiliation: Grupo Inmunovirología, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia.

ABSTRACT

Background: Dengue hemorrhagic fever (DHF) is observed in individuals that have pre-existing heterotypic dengue antibodies and is associated with increased viral load and high levels of pro-inflammatory cytokines early in infection. Interestingly, a recent study showed that dengue virus infection in the presence of antibodies resulted in poor stimulation of Toll-like receptors (TLRs), thereby facilitating virus particle production, and also suggesting that TLRs may contribute to disease pathogenesis.

Methodology/principal findings: We evaluated the expression levels of TLR2, 3, 4 and 9 and the co-stimulatory molecules CD80 and CD86 by flow cytometry. This was evaluated in monocytes, in myeloid and plasmacytoid dendritic cells (mDCs and pDCs) from 30 dengue patients with different clinical outcomes and in 20 healthy controls. Increased expression of TLR3 and TLR9 in DCs of patients with dengue fever (DF) early in infection was detected. In DCs from patients with severe manifestations, poor stimulation of TLR3 and TLR9 was observed. In addition, we found a lower expression of TLR2 in patients with DF compared to DHF. Expression levels of TLR4 were not affected. Furthermore, the expression of CD80 and CD86 was altered in mDCs and CD86 in pDCs of severe dengue cases. We show that interferon alpha production decreased in the presence of dengue virus after stimulation of PBMCs with the TLR9 agonist (CpG A). This suggests that the virus can affect the interferon response through this signaling pathway.

Conclusions/significance: These results show that during dengue disease progression, the expression profile of TLRs changes depending on the severity of the disease. Changes in TLRs expression could play a central role in DC activation, thereby influencing the innate immune response.

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Related in: MedlinePlus

Increased expression of TLRs in mDCs and pDCs of dengue-infected patients.Expression profile of TLR2, 3, 4 and 9 in mDCs (A) and pDCs (B) of dengue patients isolated at different times after the onset of disease symptoms (day 3, 5 and 15) (n = 30) and of healthy controls (n = 20). The evaluation of TLR expression was performed by flow cytometry based on mean fluorescence intensity (MFI) analysis. Data are presented as the median and 25–75 interquartile ranges Statistical analysis was performed by using the Kruskal-Wallis test followed by the Dunn's Multiple comparisons Test. *p<0.05, ** p<0.01 and ***p<0.001.
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pntd-0002060-g003: Increased expression of TLRs in mDCs and pDCs of dengue-infected patients.Expression profile of TLR2, 3, 4 and 9 in mDCs (A) and pDCs (B) of dengue patients isolated at different times after the onset of disease symptoms (day 3, 5 and 15) (n = 30) and of healthy controls (n = 20). The evaluation of TLR expression was performed by flow cytometry based on mean fluorescence intensity (MFI) analysis. Data are presented as the median and 25–75 interquartile ranges Statistical analysis was performed by using the Kruskal-Wallis test followed by the Dunn's Multiple comparisons Test. *p<0.05, ** p<0.01 and ***p<0.001.

Mentions: DCs are not only important target cells of DENV infection; they also play a central role in the innate antiviral response, through TLR activation. Therefore, we evaluated the expression levels of TLR2, TLR3, TLR4 and TLR9 in mDCs, pDCs and monocytes of dengue patients, and compared them to the HCs. In mDCs of dengue patients, TLR3, TLR4 and TLR9 reached maximum expression on day 5 of illness (Fig. 3A). The MFI results showed that expression of TLR3 in mDCs was significantly higher in dengue patients than in HCs, on days 3 and 5 of illness (p<0.05 and p<0.01, respectively; Fig. 3A). For TLR4, only at day 5 a significantly higher expression was observed (Fig. 3A). Expression of TLR9 in mDCs of dengue patients was significantly increased (p<0.05) on day 5 of illness compared to those of HCs, while expression of TLR2 in mDCs did not differ between dengue patients and HCs (Fig. 3A). Our results also show that on day 15, the level of expression of all the TLRs tested decreased to levels similar to those of HCs (Fig. 3A).


Differential expression of Toll-like receptors in dendritic cells of patients with dengue during early and late acute phases of the disease.

Torres S, Hernández JC, Giraldo D, Arboleda M, Rojas M, Smit JM, Urcuqui-Inchima S - PLoS Negl Trop Dis (2013)

Increased expression of TLRs in mDCs and pDCs of dengue-infected patients.Expression profile of TLR2, 3, 4 and 9 in mDCs (A) and pDCs (B) of dengue patients isolated at different times after the onset of disease symptoms (day 3, 5 and 15) (n = 30) and of healthy controls (n = 20). The evaluation of TLR expression was performed by flow cytometry based on mean fluorescence intensity (MFI) analysis. Data are presented as the median and 25–75 interquartile ranges Statistical analysis was performed by using the Kruskal-Wallis test followed by the Dunn's Multiple comparisons Test. *p<0.05, ** p<0.01 and ***p<0.001.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585035&req=5

pntd-0002060-g003: Increased expression of TLRs in mDCs and pDCs of dengue-infected patients.Expression profile of TLR2, 3, 4 and 9 in mDCs (A) and pDCs (B) of dengue patients isolated at different times after the onset of disease symptoms (day 3, 5 and 15) (n = 30) and of healthy controls (n = 20). The evaluation of TLR expression was performed by flow cytometry based on mean fluorescence intensity (MFI) analysis. Data are presented as the median and 25–75 interquartile ranges Statistical analysis was performed by using the Kruskal-Wallis test followed by the Dunn's Multiple comparisons Test. *p<0.05, ** p<0.01 and ***p<0.001.
Mentions: DCs are not only important target cells of DENV infection; they also play a central role in the innate antiviral response, through TLR activation. Therefore, we evaluated the expression levels of TLR2, TLR3, TLR4 and TLR9 in mDCs, pDCs and monocytes of dengue patients, and compared them to the HCs. In mDCs of dengue patients, TLR3, TLR4 and TLR9 reached maximum expression on day 5 of illness (Fig. 3A). The MFI results showed that expression of TLR3 in mDCs was significantly higher in dengue patients than in HCs, on days 3 and 5 of illness (p<0.05 and p<0.01, respectively; Fig. 3A). For TLR4, only at day 5 a significantly higher expression was observed (Fig. 3A). Expression of TLR9 in mDCs of dengue patients was significantly increased (p<0.05) on day 5 of illness compared to those of HCs, while expression of TLR2 in mDCs did not differ between dengue patients and HCs (Fig. 3A). Our results also show that on day 15, the level of expression of all the TLRs tested decreased to levels similar to those of HCs (Fig. 3A).

Bottom Line: In addition, we found a lower expression of TLR2 in patients with DF compared to DHF.This suggests that the virus can affect the interferon response through this signaling pathway.Changes in TLRs expression could play a central role in DC activation, thereby influencing the innate immune response.

View Article: PubMed Central - PubMed

Affiliation: Grupo Inmunovirología, Sede de Investigación Universitaria, Universidad de Antioquia, Medellín, Colombia.

ABSTRACT

Background: Dengue hemorrhagic fever (DHF) is observed in individuals that have pre-existing heterotypic dengue antibodies and is associated with increased viral load and high levels of pro-inflammatory cytokines early in infection. Interestingly, a recent study showed that dengue virus infection in the presence of antibodies resulted in poor stimulation of Toll-like receptors (TLRs), thereby facilitating virus particle production, and also suggesting that TLRs may contribute to disease pathogenesis.

Methodology/principal findings: We evaluated the expression levels of TLR2, 3, 4 and 9 and the co-stimulatory molecules CD80 and CD86 by flow cytometry. This was evaluated in monocytes, in myeloid and plasmacytoid dendritic cells (mDCs and pDCs) from 30 dengue patients with different clinical outcomes and in 20 healthy controls. Increased expression of TLR3 and TLR9 in DCs of patients with dengue fever (DF) early in infection was detected. In DCs from patients with severe manifestations, poor stimulation of TLR3 and TLR9 was observed. In addition, we found a lower expression of TLR2 in patients with DF compared to DHF. Expression levels of TLR4 were not affected. Furthermore, the expression of CD80 and CD86 was altered in mDCs and CD86 in pDCs of severe dengue cases. We show that interferon alpha production decreased in the presence of dengue virus after stimulation of PBMCs with the TLR9 agonist (CpG A). This suggests that the virus can affect the interferon response through this signaling pathway.

Conclusions/significance: These results show that during dengue disease progression, the expression profile of TLRs changes depending on the severity of the disease. Changes in TLRs expression could play a central role in DC activation, thereby influencing the innate immune response.

Show MeSH
Related in: MedlinePlus