A mutated cholera toxin without the ADP-ribosyltransferase activity induces cytokine production and inhibits apoptosis of splenocytes in mice possibly via toll-like receptor-4 signaling

Tie Liu, Yang Wei, Gang Liu, Bingyin Shi, Suarez Giovanni, Johnny Peterson, Ashok Chopra

Research output: Contribution to journalArticle

Abstract

Native cholera toxin (CT) and its mutated form (CT-2*) without ADP-ribosyltransferase activity differ in their immunomodulatory effects on host cells, and the mechanisms of these differences are poorly understood. In this study, we demonstrated that CT-2* induced higher levels of cytokine production and down-regulated ex-vivo apoptosis of splenocytes from C57BL/6 mice. After exposure of the splenocytes ex-vivo to CT or CT-2* (2 μg/ml) for 48 h, CT-2* stimulated expression of the toll-like receptor (TLR-4) gene was much higher and the cells produced increased levels of interleukin (IL)-12, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, compared to splenocytes of mice exposed to native CT. We confirmed these findings by observing that CT-2*, induced much lower levels of IL-12, IFN-γ, and TNF-α in a TLR-4 knockout macrophage cell line derived from C57BL/6 mice. In addition, while CT is known to stimulate apoptosis in splenocytes, we observed that CT-2* significantly down-regulated apoptosis (4.2%), compared to splenocytes exposed to CT (18.7%) or PBS (negative control, 8.5%). On the contrary, we noted both native CT and CT-2* to exhibit similar levels of apoptosis in TLR-4-/- cell line. Overall, the evidence supports the conclusion that CT-2* modulated cytokine production and apoptosis in splenocytes of mice possibly through the TLR-4 signaling pathway.

Original languageEnglish (US)
Pages (from-to)21-27
Number of pages7
JournalMolecular Immunology
Volume75
DOIs
StatePublished - Jul 1 2016
Externally publishedYes

Fingerprint

ADP Ribose Transferases
Toll-Like Receptor 4
Cholera Toxin
Apoptosis
Cytokines
Interleukin-12
Inbred C57BL Mouse
Interferons
Tumor Necrosis Factor-alpha
Cell Line

Keywords

  • Apoptosis
  • CT-2*
  • Cytokines
  • IL-12
  • Splenocyte
  • TLR4

ASJC Scopus subject areas

  • Molecular Biology
  • Immunology

Cite this

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title = "A mutated cholera toxin without the ADP-ribosyltransferase activity induces cytokine production and inhibits apoptosis of splenocytes in mice possibly via toll-like receptor-4 signaling",
abstract = "Native cholera toxin (CT) and its mutated form (CT-2*) without ADP-ribosyltransferase activity differ in their immunomodulatory effects on host cells, and the mechanisms of these differences are poorly understood. In this study, we demonstrated that CT-2* induced higher levels of cytokine production and down-regulated ex-vivo apoptosis of splenocytes from C57BL/6 mice. After exposure of the splenocytes ex-vivo to CT or CT-2* (2 μg/ml) for 48 h, CT-2* stimulated expression of the toll-like receptor (TLR-4) gene was much higher and the cells produced increased levels of interleukin (IL)-12, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, compared to splenocytes of mice exposed to native CT. We confirmed these findings by observing that CT-2*, induced much lower levels of IL-12, IFN-γ, and TNF-α in a TLR-4 knockout macrophage cell line derived from C57BL/6 mice. In addition, while CT is known to stimulate apoptosis in splenocytes, we observed that CT-2* significantly down-regulated apoptosis (4.2{\%}), compared to splenocytes exposed to CT (18.7{\%}) or PBS (negative control, 8.5{\%}). On the contrary, we noted both native CT and CT-2* to exhibit similar levels of apoptosis in TLR-4-/- cell line. Overall, the evidence supports the conclusion that CT-2* modulated cytokine production and apoptosis in splenocytes of mice possibly through the TLR-4 signaling pathway.",
keywords = "Apoptosis, CT-2*, Cytokines, IL-12, Splenocyte, TLR4",
author = "Tie Liu and Yang Wei and Gang Liu and Bingyin Shi and Suarez Giovanni and Johnny Peterson and Ashok Chopra",
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T1 - A mutated cholera toxin without the ADP-ribosyltransferase activity induces cytokine production and inhibits apoptosis of splenocytes in mice possibly via toll-like receptor-4 signaling

AU - Liu, Tie

AU - Wei, Yang

AU - Liu, Gang

AU - Shi, Bingyin

AU - Giovanni, Suarez

AU - Peterson, Johnny

AU - Chopra, Ashok

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Native cholera toxin (CT) and its mutated form (CT-2*) without ADP-ribosyltransferase activity differ in their immunomodulatory effects on host cells, and the mechanisms of these differences are poorly understood. In this study, we demonstrated that CT-2* induced higher levels of cytokine production and down-regulated ex-vivo apoptosis of splenocytes from C57BL/6 mice. After exposure of the splenocytes ex-vivo to CT or CT-2* (2 μg/ml) for 48 h, CT-2* stimulated expression of the toll-like receptor (TLR-4) gene was much higher and the cells produced increased levels of interleukin (IL)-12, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, compared to splenocytes of mice exposed to native CT. We confirmed these findings by observing that CT-2*, induced much lower levels of IL-12, IFN-γ, and TNF-α in a TLR-4 knockout macrophage cell line derived from C57BL/6 mice. In addition, while CT is known to stimulate apoptosis in splenocytes, we observed that CT-2* significantly down-regulated apoptosis (4.2%), compared to splenocytes exposed to CT (18.7%) or PBS (negative control, 8.5%). On the contrary, we noted both native CT and CT-2* to exhibit similar levels of apoptosis in TLR-4-/- cell line. Overall, the evidence supports the conclusion that CT-2* modulated cytokine production and apoptosis in splenocytes of mice possibly through the TLR-4 signaling pathway.

AB - Native cholera toxin (CT) and its mutated form (CT-2*) without ADP-ribosyltransferase activity differ in their immunomodulatory effects on host cells, and the mechanisms of these differences are poorly understood. In this study, we demonstrated that CT-2* induced higher levels of cytokine production and down-regulated ex-vivo apoptosis of splenocytes from C57BL/6 mice. After exposure of the splenocytes ex-vivo to CT or CT-2* (2 μg/ml) for 48 h, CT-2* stimulated expression of the toll-like receptor (TLR-4) gene was much higher and the cells produced increased levels of interleukin (IL)-12, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, compared to splenocytes of mice exposed to native CT. We confirmed these findings by observing that CT-2*, induced much lower levels of IL-12, IFN-γ, and TNF-α in a TLR-4 knockout macrophage cell line derived from C57BL/6 mice. In addition, while CT is known to stimulate apoptosis in splenocytes, we observed that CT-2* significantly down-regulated apoptosis (4.2%), compared to splenocytes exposed to CT (18.7%) or PBS (negative control, 8.5%). On the contrary, we noted both native CT and CT-2* to exhibit similar levels of apoptosis in TLR-4-/- cell line. Overall, the evidence supports the conclusion that CT-2* modulated cytokine production and apoptosis in splenocytes of mice possibly through the TLR-4 signaling pathway.

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