The expression levels of chemotaxis-related molecules CXC chemokine receptor 1, interleukin-8, and pro-platelet basic protein in gingival tissues.

Background/purpose: Excessive host immune response is thought to be an important cause of periodontal tissue damage during periodontitis. The potent chemotaxis produced by locally released chemokines is the key signal to trigger this response. Here, we aimed to investigate the expression of CXC chemokine receptor 1 (CXCR1), and chemokines interleukin-8 (IL-8) and pro-platelet basic protein (PPBP) in human inflammatory gingival tissues compared with healthy tissues. Materials and methods: A total of 54 human gingival tissues, 27 healthy and 27 inflammatory samples, were collected. Fifteen specimens of each group were employed for quantitative reverse transcription polymerase chain reaction to determine the mRNA levels of CXCR1, IL-8, and PPBP. Six samples of each group were used for Western blotting to investigate the protein expression of CXCR1 and for enzyme-linked immunosorbent assay to evaluate the protein levels of IL-8 and PPBP, respectively. Results: The mRNA levels of chemokine receptor CXCR1, chemokine IL-8, and PPBP in inflammatory gingival tissues were significantly higher than those in healthy controls (P < 0.05). The protein levels of CXCR1, IL-8, and PPBP in inflammatory gingival tissues were also significantly higher than those in healthy gingival tissues (P < 0.05). Conclusion: When compared to healthy gingival tissues, the expression of CXCR1, IL-8, and PPBP in inflammatory gingival tissues is higher.

Toll-like receptor 4 regulates spontaneous intestinal tumorigenesis by up-regulating IL-6 and GM-CSF.

Inflammation is as an important component of intestinal tumorigenesis. The activation of Toll-like receptor 4 (TLR4) signalling promotes inflammation in colitis of mice, but the role of TLR4 in intestinal tumorigenesis is not yet clear. About 80%-90% of colorectal tumours contain inactivating mutations in the adenomatous polyposis coli (Apc) tumour suppressor, and intestinal adenoma carcinogenesis in familial adenomatous polyposis (FAP) is also closely related to the germline mutations in Apc. The ApcMin/+ (multiple intestinal neoplasia) model mouse is a well-utilized model of FAP, an inherited form of intestinal cancer. In this study, ApcMin/+ intestinal adenoma mice were generated on TLR4-sufficient and TLR4-deficient backgrounds to investigate the carcinogenic effect of TLR4 in mouse gut by comparing mice survival, peripheral blood cells, bone marrow haematopoietic precursor cells and numbers of polyps in the guts of ApcMin/+ WT and ApcMin/+ TLR4-/- mice. The results revealed that TLR4 had a critical role in promoting spontaneous intestinal tumorigenesis. Significant differential genes were screened out by the high-throughput RNA-Seq method. After combining these results with KEGG enrichment data, it was determined that TLR4 might promote intestinal tumorigenesis by activating cytokine-cytokine receptor interaction and pathways in cancer signalling pathways. After a series of validation experiments for the concerned genes, it was found that IL6, GM-CSF (CSF2), IL11, CCL3, S100A8 and S100A9 were significantly decreased in gut tumours of ApcMin/+ TLR4-/- mice compared with ApcMin/+ WT mice. In the functional study of core down-regulation factors, it was found that IL6, GM-CSF, IL11, CCL3 and S100A8/9 increased the viability of colon cancer cell lines and decreased the apoptosis rate of colon cancer cells with irradiation and chemical treatment.

Critical role of toll-like receptor 4 (TLR4) in dextran sulfate sodium (DSS)-Induced intestinal injury and repair.

Ulcerative colitis2 (UC) is an inflammatory bowel disease3 (IBD) that causes long-lasting inflammation and ulcers in the human digestive tract. The repair function of TLR4 in the intestinal epithelium is still unknown. Here, wild-type4 (WT) mice, TLR4-knockout mice5 (KO; TLR4-/-) and commensal-depleted mice were used as dextran sulfate sodium6 (DSS)-induced or radiation-induced colitis and injury models to explore the role of TLR4 signaling in intestinal injury. Exogenous lipopolysaccharide7 (LPS) promoted DSS-induced inflammatory cytokines and aggravated intestinal damage. TLR4 deficiency and commensal bacterial depletion inhibited the toxic effects of LPS, but these mice were more susceptible to DSS-induced and radiation-induced intestinal damage. Compared with WT mice, neither DSS nor radiation promoted production of more inflammatory cytokines in the guts of TLR4-KO and commensal-depleted mice. Introducing the cytokine repair factors, PGE2 and GM-CSF, increased the cytokine levels in the guts of DSS-induced colitis mice. We hypothesized that TLR4 and its ligands repaired the epithelium after DSS-induced and radiation-induced intestinal damage by upregulating PGE2 and GM-CSF. Transwell migration assays suggested that LPS, IL6, TNF, PGE2 and GM-CSF promoted intestinal cell migration, and cell viability analysis suggested that these factors protected against radiation-induced intestinal damage. Our data underscore the importance of the balancing role of TLR4 in intestinal injury and repair.

Toll-like receptor 4 (TLR4) deficiency aggravates dextran sulfate sodium (DSS)-induced intestinal injury by down-regulating IL6, CCL2 and CSF3.

BACKGROUND: Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that causes long-lasting inflammation and ulcers in the human digestive tract. The repair role of TLR4 in the intestinal epithelium is still unknown. METHODS: By comparing to wild-type (WT) mice, Toll-like receptor 4 (TLR4)-knockout mice (TLR4-KO) were used as dextran sulfate sodium (DSS)-induced colitis models to explore the role of TLR4 signaling in intestinal injury. High-throughput RNA-Seq, RT-qPCR and ELISA were performed to screen and verify key differences in gut genes between WT and TLR4-KO mice. Functional study of core dysregulated factors was performed in intestinal cell lines. RESULTS: We found that DSS-induced intestinal injury was aggravated by LPS (TLR4 agonist) and TLR4-KO. When compared to WT mice, IL6, CCL2, CSF3, IL11, Ccnb1, Ccnd1 and TNF-α significantly decreased and Fas and FasL have increased in the gut of TLR4-KO mice. IL6, CCL2, CSF3, Fas and FasL have all increased in CT-26 cells treated with LPS. Combined with the above data and KEGG enrichment, it can be assumed that TLR4-KO might aggravate DSS-induced intestinal damage by attenuating cell cycle, cytokine-cytokine receptor interaction, and Toll-like receptor signaling pathway, and enhancing the apoptosis pathway. In the functional study of core dysregulated factors, it was found that LPS, IL6, IL11, CSF3, CCL2, S100A8, S100A9 and Mmp3 have improved viability of colon cancer cell lines and decreased apoptosis rate of mouse colon cancer cells when these were treated with DSS. However, Jo-2 (Fas agonistic monoclonal antibody) played the opposite role in colon cancer cells treated with DSS. CONCLUSIONS: TLR4 had a repairing effect on DSS-induced intestinal damage and it up-regulate IL6, CCL2 and CSF3. Fas and FasL enhanced DSS-induced colon injury in mice, but might have little to do with TLR4 signaling.