Inhibition of IRAK 1/4 alleviates colitis by inhibiting TLR4/ NF-κB pathway and protecting the intestinal barrier

Bosn J Basic Med Sci. 2022 Oct 23;22(6):872-881. doi: 10.17305/bjbms.2022.7348.

Abstract

Interleukin-1 receptor-associated kinase 1/4 (IRAK1/4) is the main kinase of the Toll-like receptor (TLR)-mediated pathway, considered a new target for treating inflammatory diseases. Studies showed a significant correlation between TLRs and inflammatory responses in ulcerative colitis (UC). Therefore, in this study, after inducing experimental colitis in mice with 3% dextran sulfate sodium (DSS), different concentrations of IRAK1/4 inhibitors were administered intraperitoneally. Then, the disease activity index was assessed, including the degree of pathological damage, by HE staining. Subsequently, while western blotting detected the TLR4/NF-κB pathway and intestinal barrier protein expression (Zonula-1, Occludin, Claudin-1, JAM-A), real-time polymerase chain reaction (RT-PCR) detected the mRNA expression levels of IRAK1/4 and mucin1/2. Furthermore, the expression levels of Zonula-1 and occludin were detected by immunofluorescence, including the plasma FITC-dextran 4000 concentration, to evaluate intestinal barrier permeability. However, ELISA measured the expression of inflammatory factors to reflect intestinal inflammation in mice. Investigations showed that the IRAK 1/4 inhibitor significantly reduced clinical symptoms and pathological DSS-induced colitis damage in mice and then inhibited the cytoplasmic and nuclear translocation of NF-κB p65, including the phosphorylation of IκBα and reduction in downstream inflammatory factor production. Therefore, we established that the IRAK1/4 inhibitor effectively improves colitis induced by DSS, partly by inhibiting the TLR4/NF-κB pathway, reducing inflammation, and maintaining the integrity of the colonic barrier.

MeSH terms

  • Animals
  • Claudin-1 / metabolism
  • Colitis* / chemically induced
  • Colitis* / drug therapy
  • Colitis, Ulcerative* / chemically induced
  • Colitis, Ulcerative* / drug therapy
  • Dextran Sulfate / toxicity
  • Disease Models, Animal
  • Inflammation
  • Interleukin-1 Receptor-Associated Kinases / antagonists & inhibitors
  • Interleukin-1 Receptor-Associated Kinases / metabolism
  • Mice
  • Mice, Inbred C57BL
  • NF-KappaB Inhibitor alpha / metabolism
  • NF-kappa B / metabolism
  • Occludin / metabolism
  • RNA, Messenger
  • Signal Transduction
  • Toll-Like Receptor 4 / metabolism

Substances

  • Claudin-1
  • Dextran Sulfate
  • Interleukin-1 Receptor-Associated Kinases
  • NF-kappa B
  • NF-KappaB Inhibitor alpha
  • Occludin
  • RNA, Messenger
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4