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Dendritic Cells Regulate Treg-Th17 Axis in Obstructive Phase of Bile Duct Injury in Murine Biliary Atresia.

Liu YJ, Li K, Yang L, Tang ST, Wang XX, Cao GQ, Li S, Lei HY, Zhang X - PLoS ONE (2015)

Bottom Line: By depleting the Th17 cells, the BA symptoms (onset of jaundice, acholic stools and retarded growth) were attenuated and the survival rate was improved.The level of IL-6, which has been shown to be abundantly secreted by activated dendritic cells (DCs), was remarkably elevated.In conclusion, the DC-regulated Treg-Th17 axis, probably in conjunction with other effector T cells, aggravates progressive inflammatory injury at the time of ductal obstruction.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatric Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

ABSTRACT
Several cell types are considered to be effector cells in bile duct injury in rhesus rotavirus (RRV)-induced experimental biliary atresia (BA). Here, we identified an increased T helper 17 (Th17) cell population in a BA mode. By depleting the Th17 cells, the BA symptoms (onset of jaundice, acholic stools and retarded growth) were attenuated and the survival rate was improved. Furthermore, we found that in mice with BA, the percentage of CD4+CD25highFoxp3+ T regulatory (Treg) cells decreased along with the increased percentage of Th17 cells. However, the absolute numbers of Treg and Th17 cells were both increased in liver of RRV-injected mice compared to saline-injected mice. The proportion of Th17 cells at 7 days post-infection was decreased if Treg cells isolated from normal adult mice, but not Treg cells from the livers of mice with BA, were intraperitoneally transferred on day 5 of life. In vitro experiments also showed that Treg cells from mice with BA had a diminished suppressive effect on Th17 cell generation. To determine the mechanisms, we investigated the production of cytokines in the liver. The level of IL-6, which has been shown to be abundantly secreted by activated dendritic cells (DCs), was remarkably elevated. Importantly, in a Treg/Th17 cell suppression assay, IL-6 was demonstrated to paralyze the Treg cells' suppressive effect on Th17 cells and eventually the unrestrained increase of Th17 cells contributed to bile duct injury. In conclusion, the DC-regulated Treg-Th17 axis, probably in conjunction with other effector T cells, aggravates progressive inflammatory injury at the time of ductal obstruction.

No MeSH data available.


Related in: MedlinePlus

Adoptive transfer of normal Treg cells into BA mice suppresses RRV-induced generation of Th17 cells.Saline or RRV was injected within 12 hrs of birth. Tregs were injected i.p. 3 days post infection. (A) Representative FCM diagrams of Th17 cells from liver of RRV primed 7 days old mice. *** P<0.001, ** P<0.01, n = 11. (B) Hepatic mRNA for genes encoding IL-17A and its transcription factor ROR-γt were quantified by real-time PCR and expressed as fold change (vertical axis) in mice with BA over controls, n = 9 for biliary atresia and n = 7 for controls; all fold changes were statistically significant at * P<0.05, ** P<0.01. (C) Immunofluorescence staining of liver frozen sections of mice at day 7 post infection. Antibodies to CD4 (Green) and IL-17A (Red) were added to distinguish CD4+ cells and IL-17A+ cells. Antibodies to Cytokine 7 (Khaki) indicate the bile duct lumen. Nucleus were stained by DAPI (Blue). Magnification x200. * P<0.05. Representative of 4 experiments.
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pone.0136214.g004: Adoptive transfer of normal Treg cells into BA mice suppresses RRV-induced generation of Th17 cells.Saline or RRV was injected within 12 hrs of birth. Tregs were injected i.p. 3 days post infection. (A) Representative FCM diagrams of Th17 cells from liver of RRV primed 7 days old mice. *** P<0.001, ** P<0.01, n = 11. (B) Hepatic mRNA for genes encoding IL-17A and its transcription factor ROR-γt were quantified by real-time PCR and expressed as fold change (vertical axis) in mice with BA over controls, n = 9 for biliary atresia and n = 7 for controls; all fold changes were statistically significant at * P<0.05, ** P<0.01. (C) Immunofluorescence staining of liver frozen sections of mice at day 7 post infection. Antibodies to CD4 (Green) and IL-17A (Red) were added to distinguish CD4+ cells and IL-17A+ cells. Antibodies to Cytokine 7 (Khaki) indicate the bile duct lumen. Nucleus were stained by DAPI (Blue). Magnification x200. * P<0.05. Representative of 4 experiments.

Mentions: Different studies have shown that AT of normal Treg or of CD4+ T cells containing Treg cells can restrain the inflammatory response to a viral challenge. Based on this, we hypothesized that Treg cells may also suppress the generation of Th17 cells. To explore the possibility that Treg cells may suppress Th17 differentiation in vivo, normal splenic Treg cells were purified and transferred into mice at 3 days post-RRV infection where the Th17 cells began to increase rapidly (S2 Fig). Following AT, the frequency of Th17 cells was significantly reduced at day 7 post-infection (Fig 4A). This decreased frequency was associated with downregulation of the hepatic expression of IL-17A and ROR-γt mRNA in these mice compared with mice without AT (Fig 4B). Immunofluorescence staining further demonstrated that the expression of IL-17A and ROR-γt was reduced around bile duct areas after AT (Fig 4C).


Dendritic Cells Regulate Treg-Th17 Axis in Obstructive Phase of Bile Duct Injury in Murine Biliary Atresia.

Liu YJ, Li K, Yang L, Tang ST, Wang XX, Cao GQ, Li S, Lei HY, Zhang X - PLoS ONE (2015)

Adoptive transfer of normal Treg cells into BA mice suppresses RRV-induced generation of Th17 cells.Saline or RRV was injected within 12 hrs of birth. Tregs were injected i.p. 3 days post infection. (A) Representative FCM diagrams of Th17 cells from liver of RRV primed 7 days old mice. *** P<0.001, ** P<0.01, n = 11. (B) Hepatic mRNA for genes encoding IL-17A and its transcription factor ROR-γt were quantified by real-time PCR and expressed as fold change (vertical axis) in mice with BA over controls, n = 9 for biliary atresia and n = 7 for controls; all fold changes were statistically significant at * P<0.05, ** P<0.01. (C) Immunofluorescence staining of liver frozen sections of mice at day 7 post infection. Antibodies to CD4 (Green) and IL-17A (Red) were added to distinguish CD4+ cells and IL-17A+ cells. Antibodies to Cytokine 7 (Khaki) indicate the bile duct lumen. Nucleus were stained by DAPI (Blue). Magnification x200. * P<0.05. Representative of 4 experiments.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4556529&req=5

pone.0136214.g004: Adoptive transfer of normal Treg cells into BA mice suppresses RRV-induced generation of Th17 cells.Saline or RRV was injected within 12 hrs of birth. Tregs were injected i.p. 3 days post infection. (A) Representative FCM diagrams of Th17 cells from liver of RRV primed 7 days old mice. *** P<0.001, ** P<0.01, n = 11. (B) Hepatic mRNA for genes encoding IL-17A and its transcription factor ROR-γt were quantified by real-time PCR and expressed as fold change (vertical axis) in mice with BA over controls, n = 9 for biliary atresia and n = 7 for controls; all fold changes were statistically significant at * P<0.05, ** P<0.01. (C) Immunofluorescence staining of liver frozen sections of mice at day 7 post infection. Antibodies to CD4 (Green) and IL-17A (Red) were added to distinguish CD4+ cells and IL-17A+ cells. Antibodies to Cytokine 7 (Khaki) indicate the bile duct lumen. Nucleus were stained by DAPI (Blue). Magnification x200. * P<0.05. Representative of 4 experiments.
Mentions: Different studies have shown that AT of normal Treg or of CD4+ T cells containing Treg cells can restrain the inflammatory response to a viral challenge. Based on this, we hypothesized that Treg cells may also suppress the generation of Th17 cells. To explore the possibility that Treg cells may suppress Th17 differentiation in vivo, normal splenic Treg cells were purified and transferred into mice at 3 days post-RRV infection where the Th17 cells began to increase rapidly (S2 Fig). Following AT, the frequency of Th17 cells was significantly reduced at day 7 post-infection (Fig 4A). This decreased frequency was associated with downregulation of the hepatic expression of IL-17A and ROR-γt mRNA in these mice compared with mice without AT (Fig 4B). Immunofluorescence staining further demonstrated that the expression of IL-17A and ROR-γt was reduced around bile duct areas after AT (Fig 4C).

Bottom Line: By depleting the Th17 cells, the BA symptoms (onset of jaundice, acholic stools and retarded growth) were attenuated and the survival rate was improved.The level of IL-6, which has been shown to be abundantly secreted by activated dendritic cells (DCs), was remarkably elevated.In conclusion, the DC-regulated Treg-Th17 axis, probably in conjunction with other effector T cells, aggravates progressive inflammatory injury at the time of ductal obstruction.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatric Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

ABSTRACT
Several cell types are considered to be effector cells in bile duct injury in rhesus rotavirus (RRV)-induced experimental biliary atresia (BA). Here, we identified an increased T helper 17 (Th17) cell population in a BA mode. By depleting the Th17 cells, the BA symptoms (onset of jaundice, acholic stools and retarded growth) were attenuated and the survival rate was improved. Furthermore, we found that in mice with BA, the percentage of CD4+CD25highFoxp3+ T regulatory (Treg) cells decreased along with the increased percentage of Th17 cells. However, the absolute numbers of Treg and Th17 cells were both increased in liver of RRV-injected mice compared to saline-injected mice. The proportion of Th17 cells at 7 days post-infection was decreased if Treg cells isolated from normal adult mice, but not Treg cells from the livers of mice with BA, were intraperitoneally transferred on day 5 of life. In vitro experiments also showed that Treg cells from mice with BA had a diminished suppressive effect on Th17 cell generation. To determine the mechanisms, we investigated the production of cytokines in the liver. The level of IL-6, which has been shown to be abundantly secreted by activated dendritic cells (DCs), was remarkably elevated. Importantly, in a Treg/Th17 cell suppression assay, IL-6 was demonstrated to paralyze the Treg cells' suppressive effect on Th17 cells and eventually the unrestrained increase of Th17 cells contributed to bile duct injury. In conclusion, the DC-regulated Treg-Th17 axis, probably in conjunction with other effector T cells, aggravates progressive inflammatory injury at the time of ductal obstruction.

No MeSH data available.


Related in: MedlinePlus