Lactobacillus crispatus M206119 exacerbates murine DSS-colitis by interfering with inflammatory responses

AIM： TO investigate the role of Lactobacillus crispatus （L. crispatus） strain China Center for Type Culture Col- lection （CCTCC） M206119 in intestinal inflammation.METHODS： Forty 8-wk-old Balb/c mice （20± 2 g） were divided into four groups of 10 mice each. Three groups that had received dextran sulfate sodium （DSS） were administered normal saline, sulfasalazine or CCTCC M206119 strain, and the fourth group received none of these. We assessed the severity of colitis using a disease activity index, measured the colon length and weight, collected stools and mesenteric lymph nodes for bacterial microflora analysis. One centimeter of the proximal colon, middle colon and distal colon were collected and fixed in 10% buffered formalin, dehydrated in ethanol, and embedded in paraffin. Interleukin （IL）- 1β, IL-6 and tumor necrosis factor （TNF）-α expression was detected using reverse transcription polymerase chain reaction. Protective factors zonula occludens （ZO）-1 and β-defensin 2 were detected by immunoblot-ting. The features of CCTCC M206119 strain were identified based on morphology, biochemical profile, and 16S RNA sequencing.RESULTS： DSS-colitis animals treated with CCTCC M206119 had markedly more severe disease, with greater weight loss, diarrhea, fecal bleeding, and shortened colon length. In addition, the CCTCC-M206119- treated group had comparatively higher histologi- cal scores and more neutrophil infiltration than the controls. Expression of protective factors ZO-1 and β-defensin 2 was downregulated due to destruction of the mucosal barrier after CCTCC M206119 strain treatment. An in vitro assay demonstrated that CCTCC M206119 strain increased the nuclear translocation of nuclear factor-κB in epithelial cells. Intestinal proinflam- matory or anti-inflammatory cytokine responses were evaluated. Proinflammatory colonic cytokine （IL-Iβ, IL-6 and TNF-α） levels were clearly increased in CCTCC- M206119-treated animals, whereas anti-inflammatory colonic cytokine （IL-10） level was lowered compared with saline or 5-aminosalicylic-acid-treated DSS-colitis mice. Next, CCTCC M206119 strain was characterized as 1. crispatus by microscopic morphology, biochemical tests and 16S rRNA gene level.CONCLUSION： Not all lactobacilli are beneficial for in- testinal inflammation, and L. crispatus CCTCC M206119 strain is involved in exacerbation of intestinal inflamma- tion in DSS-colitis mice.

Effects of the Overall Alkaloid of a Traditional Chinese Medicine “Tongbiling” on the Cytokine Expression in Th1 and Th2 Cells of Rheumatoid Arthritis and Their Signaling Pathway

To investigate the effects of overall alkali of a traditional Chinese medicine “Tongbiling” (brucine and strychnine alkaloids in main) on the cytokines expression in Th1 and Th2 cells in the synovial fluid of patients with rheumatism arthritis and their signal pathway, the mononuclear cells in the synovial fluid (SFMC) of patients were isolated by Ficoll-Hypaque gradient centrifugation, and the CD3 + CD69 + and CD3 + HLA-DR antigen were analyzed by flow cytometry in comparison with those of the peripheral blood. The rest of cells were cultured after resuspension with RPMI 1640 culture medium. Phorbol 12,13-dibutyrate (PDB) and ionomycin were added successively into the culture with various concentration of overall alkali Tongbiling (TBL). After 4 h of cultivation, the expression of IFN-γ and IL-4 in CD3 + cells were analyzed by flow cytometry. The influence of overall alkali TBL (100?mg/L) on the intracellular calcium was investigated after Fluo-3/AM labeling and stimulation with PDB and ionomycin at 1, 2, 4 and 10?min, and the influence of TBL on the expression of CD3 + CD69 + cells were determined with stimulation of PDB for 24?h in the whole blood lymphocytes culture. It was found that the percentage of T cells bearing CD69 was significantly up-regulated (77%), while that of T cells bearing HLA-DR was 44% in the synovial mononucleated cells. After PDB and ionomycin stimulation, the expression of IFN-γ in CD3 + cells were up-regulated, but there was no change on the expression of IL-4 in CD3 + cells, indicating that ratio of Th1/Th2 was significantly increased and Th cells differentiate to Th1 cells in mainly. Four concentrations of overall alkaloid of TBL (200?mg/L, 100?mg/L, 50?mg/L, 25?mg/L) could down-regulated the expression of IFN-γ in CD3 + cells and the Th1/Th2 ratio obviously, but all the concentrations of the overall alkaloids had no effect on the expression of IL-4 in CD3 + cells. 100?mg/L concentration of the overall alkaloid did not down-regulate the intracellular calcium level. Each concentration of the overall alkaloid could down-regulated the expression CD69 obviously on the PDB-activated mouse T cells. It concluded from the above observations that the overall alkaloid of TBL could relieve the inflammatory and immune damages by suppressing the expression of Th1 type cytokines and Th1 cell differentiation, regulating the imbalance of Th1/Th2 cells and inhibiting the early activation of the T lymphocytes bearing CD69. There was no remarkable influence on the intracellular calcium signaling transduction pathway. The inhibitory effected on T cells to express IFN-γ might be due to the suppression of PKC-MAPK signaling pathway. From the standpoint of traditional Chinese medicine, this might be due to the regulation of “Yin” and “Yang” imbalance of joints to modify the pathological status in rheumatoid arthritis. This study provided an experimental basis for the application of overall alkaloids of TBL in the treatment of rheumatoid arthritis.

IL-17A-dependent gut microbiota is essential for regulating diet-induced disorders in mice

The gut microbiota plays a key role in obesity and related metabolic disorders, and multiple factors including diet, host genotype, and age regulate it. Many studies have examined the contribution of extrinsic factors to the regulation of the gut microbiota, but the importance of the host genetic constitution cannot be ignored, lnterleukin 17A （lL-17A）, a pro-inflammatory cytokine, is important in the defense against infection and diseases. Here, we investigated the association among IL-17, a high-fat diet （HFD）, and the gut microbiota. Mice deficient in 1L-17A were resistant to diet-induced obesity and related diseases. Compared with the I1-17a^-/1 mice, wild-type （WT） mice challenged with HFD showed obvious weight fluctuations, such as those seen in type 2 diabetes, and hematological changes similar to those associated with metabolic syndrome. However, housing WT mice and Il-17a^-/- mice together signifi- cantly alleviated these symptoms in the WT mice. A metagenomic analysis of the mouse feces indicated that the microbial community compositions of these two groups differed before HFD feeding. The HFD mediated shifts in the gut microbial compositions, which were associated with the mouse phenotypes. We also identified potentially beneficial and harmful species present during this period, and drew net- works of the most abundant species. A functional analysis indicated pathway changes in the WT and I1-17a^- /- mice when fed the HFD. Collectively, these data underscore the importance of the host factor IL-17A in shaping and regulating the gut microbiota, which conversely, influences the host health.