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In vivo microRNA-155 expression influences antigen-specific T cell-mediated immune responses generated by DNA vaccination.

Mao CP, He L, Tsai YC, Peng S, Kang TH, Pang X, Monie A, Hung CF, Wu TC - Cell Biosci (2011)

Bottom Line: Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect.Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA. wutc@jhmi.edu.

ABSTRACT

Background: MicroRNA (miRNA) molecules are potent mediators of post-transcriptional gene silencing that are emerging to be critical in the regulation of innate and adaptive immunity.

Results: Here we report that miR-155--an oncogenic miRNA with important function in the mammalian immune system--is induced in dendritic cells (DCs) upon maturation and potentially attenuates their ability to activate T cells. Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect. Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.

Conclusions: These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses. Modulation of miR-155 expression in epidermis therefore represents a potentially promising form of gene therapy for the control of diseases ranging from autoimmunity to cancer and viral infection.

No MeSH data available.


Related in: MedlinePlus

Characterization of miR-155 expression in BMDCs using RT-PCR. Total RNA was purified from 1 × 107 cultured BMDCs and enriched for small RNA species. Endpoint RT-PCR was then performed using primers directed against miR-155 to detect the presence of this miRNA in DCs. Expression of GAPDH was also tested to validate the assay. RNA from DC-1 and HEK 293 cells was used as a positive and negative control, respectively.
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Figure 1: Characterization of miR-155 expression in BMDCs using RT-PCR. Total RNA was purified from 1 × 107 cultured BMDCs and enriched for small RNA species. Endpoint RT-PCR was then performed using primers directed against miR-155 to detect the presence of this miRNA in DCs. Expression of GAPDH was also tested to validate the assay. RNA from DC-1 and HEK 293 cells was used as a positive and negative control, respectively.

Mentions: To determine whether miR-155 has biological significance in DCs, we first assayed for endogenous expression of this miRNA in BMDCs stimulated with the TLR4 agonist LPS. Endpoint RT-PCR was then performed using small RNA isolated from BMDCs with primers specific for miR-155. As shown in Figure 1, a band was observed at ~90 base pairs in the LPS-pulsed BMDC RNA-loaded lane. The location of this band is consistent with the approximate expected size of the RT-PCR-amplified miRNA product, indicating that miR-155 is present in activated DCs. Significantly, no miR-155 was observed in BMDCs left untreated with LPS, suggesting that this miRNA is induced upon maturation and thus may play an important role in the inflammatory response. The DC-1 and 293T cell lines were assessed for miR-155 expression as positive and negative controls, respectively.


In vivo microRNA-155 expression influences antigen-specific T cell-mediated immune responses generated by DNA vaccination.

Mao CP, He L, Tsai YC, Peng S, Kang TH, Pang X, Monie A, Hung CF, Wu TC - Cell Biosci (2011)

Characterization of miR-155 expression in BMDCs using RT-PCR. Total RNA was purified from 1 × 107 cultured BMDCs and enriched for small RNA species. Endpoint RT-PCR was then performed using primers directed against miR-155 to detect the presence of this miRNA in DCs. Expression of GAPDH was also tested to validate the assay. RNA from DC-1 and HEK 293 cells was used as a positive and negative control, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3116247&req=5

Figure 1: Characterization of miR-155 expression in BMDCs using RT-PCR. Total RNA was purified from 1 × 107 cultured BMDCs and enriched for small RNA species. Endpoint RT-PCR was then performed using primers directed against miR-155 to detect the presence of this miRNA in DCs. Expression of GAPDH was also tested to validate the assay. RNA from DC-1 and HEK 293 cells was used as a positive and negative control, respectively.
Mentions: To determine whether miR-155 has biological significance in DCs, we first assayed for endogenous expression of this miRNA in BMDCs stimulated with the TLR4 agonist LPS. Endpoint RT-PCR was then performed using small RNA isolated from BMDCs with primers specific for miR-155. As shown in Figure 1, a band was observed at ~90 base pairs in the LPS-pulsed BMDC RNA-loaded lane. The location of this band is consistent with the approximate expected size of the RT-PCR-amplified miRNA product, indicating that miR-155 is present in activated DCs. Significantly, no miR-155 was observed in BMDCs left untreated with LPS, suggesting that this miRNA is induced upon maturation and thus may play an important role in the inflammatory response. The DC-1 and 293T cell lines were assessed for miR-155 expression as positive and negative controls, respectively.

Bottom Line: Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect.Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA. wutc@jhmi.edu.

ABSTRACT

Background: MicroRNA (miRNA) molecules are potent mediators of post-transcriptional gene silencing that are emerging to be critical in the regulation of innate and adaptive immunity.

Results: Here we report that miR-155--an oncogenic miRNA with important function in the mammalian immune system--is induced in dendritic cells (DCs) upon maturation and potentially attenuates their ability to activate T cells. Biolistic epidermal transfection with DNA encoding miR-155 suppressed the induction of antigen-specific T cell-mediated immunity, whereas reduction of endogenous miR-155 by a partially complementary antisense sequence reversed this effect. Because DCs represent a significant component of epidermal tissue and are among the most potent of antigen-presenting cells, the inhibitory actions of miR-155 could be mediated through this subset of cells.

Conclusions: These results suggest that miR-155 may repress the expression of key molecules involved in lymph node migration, antigen presentation, or T cell activation in DCs, and thus forms part of a negative regulatory pathway that dampens the generation of T cell-mediated immune responses. Modulation of miR-155 expression in epidermis therefore represents a potentially promising form of gene therapy for the control of diseases ranging from autoimmunity to cancer and viral infection.

No MeSH data available.


Related in: MedlinePlus