The Effect of Denatured Flagellin on Toll-Like Receptor-5 (TLR-5) in Mice

Author(s): Soha Mcheik, Nayla S. Al-Akl, Alexander M. Abdelnoor*.

Journal Name: Endocrine, Metabolic & Immune Disorders - Drug Targets

Volume 18 , Issue 4 , 2018

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Abstract:

Background: Previous studies have demonstrated that flagellin, a component of bacterial flagella, engages Toll-Like receptor 5 (TLR-5) causing the activation of the Myeloid Differentiation Factor-88 (MYD-88) pathway that leads to the production of pro-inflammatory cytokines including Tumor Necrosis Factor–alpha (TNF-α) and Interleukin-12 (IL-12). In physiological levels, cytokines can aid in protection against infectious agents. However, excessive production of cytokines can lead to septic shock during sepsis.

Objective: In this study, we aimed at investigating the effect of denatured flagellin on hindering the effects induced by intact flagellin or flagellated Pseudomonas aeruginosa on the Toll-Like Receptor-5 (TLR-5) in mice.

Methods: Mouse mononuclear cells (MNCs) were cultured with intact flagellin, heat-denatured flagellin, TLR-5 antagonist, Pseudomonas aeruginosa, and TLR-4 antagonist each alone or in combinations. Supernatants were collected at 4 hours post incubation to assess the levels of IL-12 and TNF-α by Enzyme-Linked ImmunoAssay (ELISA). Furthermore, groups of BALB/c mice were injected intraperitoneally (IP) with Pseudomonas aeruginosa, LPS-RS, intact flagellin, and denatured flagellin, each alone or in different combinations. Serum levels of IL-12 and TNF-α were measured at 2, 4, and 6 hours post injections of Pseudomonas aeruginosa or intact flagellin.

Results: Pretreatment with denatured flagellin significantly reduced the amount of TNF-α and IL-12 produced both in vitro and in vivo by intact flagellin or Pseudomonas aeruginosa.

Conclusion: Denatured flagellin suppressed the production of the pro-inflammatory cytokines induced by intact flagellin or Pseudomonas aeruginosa both in vitro and in vivo, probably by blocking TLR5. Denatured flagellin might be considered as an anti-septic shock agent.

Keywords: TLR-5, flagellin, Anti-mTLR5-IgG, TLR-4, LPS-RS, cytokines.

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Article Details

VOLUME: 18
ISSUE: 4
Year: 2018
Page: [412 - 416]
Pages: 5
DOI: 10.2174/1871530318666180327115448
Price: $58

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