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

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.

Gut Protective Effect from Newly Isolated Bacteria as Probiotics against Dextran Sulfate Sodium and Carrageenan-Induced Ulcerative Colitis

“…Protein expression analyses in the colon may also suggest that certain bacteria could work to alleviate UC symptoms via the modulation of the PI3K/AKT and/or interleukin-1 receptor-associated kinase (IRAK) signaling pathways. The IRAK is the main kinase of the toll-like receptor (TLR)-mediated signaling pathway, which has been considered as a new target for treating several inflammatory diseases [ 34 ].…”

Modified Prebiotic-Based “Shield” Armed Probiotics with Enhanced Resistance of Gastrointestinal Stresses and Prolonged Intestinal Retention for Synergistic Alleviation of Colitis

“…In vivo immunofluorescence staining analysis was carried out according to the previous study . Paraffin colon tissue sections were first dewaxed and then used for ZO-1 and Occludin expression immunofluorescence detection.…”

“…In vivo immunofluorescence staining analysis was carried out according to the previous study. 60 Paraffin colon tissue sections were first dewaxed and then used for ZO-1 and Occludin expression immunofluorescence detection. Colon tissue slices were incubated overnight with antibodies against ZO-1 (1:100, Invitrogen, USA) and Occludin (1:200, Invitrogen, USA) at 4 °C.…”