Objective:To investigate the impact of recombinant flagellin targeting TLR5 and NLRC4 simultaneously or respectively on innate immune cells in mice. Methods: Induction,expression,purification and identification of recombiant FliC,which were FliC(activating both TLR5 and NLRC4);FliCΔ90-97(unable to activate TLR5),FliC-L3A(unable to activate NLRC4),FliCΔ90-97:L3A(unable to activate both TLR5 and NLRC4). The mice were divided into five groups,namely group FliC,FliC-L3A,FliCΔ90-97,FliCΔ90-97:L3A and PBS,which were injected with 100μl PBS or 10μg recombinant flagellin intraperitoneally,three mice in each group. 12 h later,the mice were executed using dislocation of cervical vertebra and the splenic and peritoneal cells were isolated. The spleen was grinded into single-cell suspension. The proportion of neutrophils,NK cells,DCs and the expression level of CD80 and CD86 on DCs were evaluated with flow cytometry. Results:Group FliC,group FliC-L3A and group FliCΔ90-97 shared the similar proportion of neutrophils in peritoneal cavity ( P>0. 05 ) , and all of which were significantly higher than group PBS and group FliCΔ90-97 ( P<0. 01),and NK cells also showed the similar trend. Compared with group FliCΔ90-97 and FliCΔ90-97:L3A,the mean fluorescence intensities(MFIs) of CD80 and CD86 in group FliC and FliC-L3A increased significantly(P<0. 01). The proportion of Treg in spleen was highest among all groups. Conclusion:Activation of TLR5 and NLRC4 had similar chemotaxis of neutrophils and NK cells. The ex-pression of CD80 and CD86 on DCs were upregulated after stimulation by flagellin and TLR5-dependent. Activation of TLR5,but not NLRC4,increased the proportion of Treg in spleen.

Objective:To explore the impact of TLR5 and NLRC4 activation on the proliferation of different breast cancer cell lines,MCF-7 and MDA-MB-23 i.Methods:Induction,expression,purification and identification of recombiant flagellin,including FliC (activating both TLR5 and NLRC4),FliC△90-97 (unable to activate TLR5),FliC-L3A (unable to activate NLRC4),FliC△90-97:L3A (unable to activate both TLR5 and NLRC4).Using different concentration of recombinant flagellin to stimulate MCF-7 and MDA-MB-231 cell lines,72 h later,the proliferation of tumor cells were detected with CCK8.We also used soft AGAR forming experiments to detect the inhibition ratio of recombinant flagellin on breast cancer cell lines.Briefly,1 000 cells were plated in the 6-well plate,then stimulated with 1 μg/ml recombinant flagellin,14 days later,the number of cloning were counted after crystal violet staining.Results:After stimulation with four recombinant flagellins at the concentration of 0.1 μ,g/ml,the inhibition ratio on MCF-7 reached 30％,and FliC△90-97 were dose-dependent on the inhibition of MCF-7 proliferation.At the concentration of 1 μg/ml,FliC-L3A which only activated TLR5 showed stronger inhibition ratio than FliC.FliC△90-97:L3A which did not activate both TLR5 and NLRC4 also inhibited the proliferation of MCF-7.After adding transfection reagent,four recombinant flagellins showed inhibition effect on MDA-MB-231.Conclusion:Flagellin can inhibit the proliferation of MCF-7 and MDA-MB-231,and the mechanism of inhibition on the proliferation were not TLR5 and NLRC4 pathway dependent.There might exist new mechanisms to explain this phenomenon.

Objective:To explore the expression and location of TLR5 and NLRC4 on different breast cancer cell lines MDA-MB-231,MCF-7 and MDA-MB-435 and TLR5 activation in breast cancer cell line by recombinant flagellin . Methods:The mRNA level of TLR5 and NLRC4 in MDA-MB-231, MCF-7 and MDA-MB-435 cell were detected with quantitative Real-time PCR and TLR5 expression and location in MDA-MB-231 and MCF-7 cell were detected with Flow cytometry. Induction,expression,purification and i-dentification of recombiant flagellin,including FliC (activating both TLR5 and NLRC4),FliC△90-97(unable to activate TLR5),FliC-L3A (unable to activate NLRC4),FliC△90-97:L3A (unable to activate both TLR5 and NLRC4). 1 μg/ml recombinant flagellin were used to stimulate MCF-7 cell lines,12 h later,the supernate were collected,and ELISA was performed to assess the secretion of IL-8. Results:The mRNA level of TLR5 in MCF-7 cell was 1 700 folds higher than that of MDA-MB-435. TLR5 was expressed in MCF-7 cell surface and ctyosol,while expressed only in cytosol in MDA-MB-231 cell. FliC and FliC-L3A,which were able to activate TLR5 pathway,stimualted MCF-7 cell line to secret IL-8,but FliC△90-97 and FliC△90-97:L3A did not. Conclusion:TLR5 and NLRC4 have been expressed in different breast cancer lines,but there exists difference on the expression level and location of TLR5. Expression level of TLR5 and NLRC4 in MCF-7 cell were higher than other breast cancer lines. TLR5 receptor which is expressed on the surface of breast cancer cell can be activated by flagellin,and these work also provide us experimental basis to further understand the impact of TLR5 activation on breast cancer cell proliferation.

This study was performed to explore the effect of flagellin+rapamycin on the growth and metastasis of 4T1 breast cancer in tumor-bearing mice,and their regulatory effect on several immunocytes.4T1 cell line was applied to establish an breast cancer model in Balb/c mice,which then injected with flagellin+rapamycin,and the volume and inhibition rate of tumor were recorded.MTT assay was used to detect the inhibitory effect of flagellin+rapamycin against 4T1 cells.Data showed that the combination of flagellin and rapamycin had the best inhibition effect on 4T1 cells,and the same results were found in animal model experiments.Flow cytometry result indicated that flagellin+rapamycin significantly down-regulated the levels of CD11b+Gr-1+myeloid-derived suppressor cells(MDSCs)and CD11b+F4/80+tumor-associated macrophages(TAMs)of tumor-bearing mice.Furthermore,flagellin+rapamycin alleviates the metastasis of 4T1 cancer cells into liver and lung.Taken together,flagellin+rapamycin can inhibit proliferation and metastasis of 4T1 cells,thus exert antitumor effects in mice,which may related with its regulatory effects on immunocytes in tumor microenvironment.

Objective:To investigate the effects of continuous renal replacement therapy (CRRT) on plasma concentration, clinical efficacy and safety of colistin sulfate.Methods:Clinical data of patients received with colistin sulfate were retrospectively analyzed from our group's previous clinical registration study, which was a prospective, multicenter observation study on the efficacy and pharmacokinetic characteristics of colistin sulfate in patients with severe infection in intensive care unit (ICU). According to whether patients received blood purification treatment, they were divided into CRRT group and non-CRRT group. Baseline data (gender, age, whether complicated with diabetes, chronic nervous system disease, etc), general data (infection of pathogens and sites, steady-state trough concentration, steady-state peak concentration, clinical efficacy, 28-day all-cause mortality, etc) and adverse event (renal injury, nervous system, skin pigmentation, etc) were collected from the two groups.Results:A total of 90 patients were enrolled, including 22 patients in the CRRT group and 68 patients in the non-CRRT group. ① There was no significant difference in gender, age, basic diseases, liver function, infection of pathogens and sites, colistin sulfate dose between the two groups. Compared with the non-CRRT group, the acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and sequential organ failure assessment (SOFA) were higher in the CRRT group [APACHE Ⅱ: 21.77±8.26 vs. 18.01±6.34, P < 0.05; SOFA: 8.5 (7.8, 11.0) vs. 6.0 (4.0, 9.0), P < 0.01], serum creatinine level was higher [μmol/L: 162.0 (119.5, 210.5) vs. 72.0 (52.0, 117.0), P < 0.01]. ② Plasma concentration: there was no significant difference in steady-state trough concentration between CRRT group and non-CRRT group (mg/L: 0.58±0.30 vs. 0.64±0.25, P = 0.328), nor was there significant difference in steady-state peak concentration (mg/L: 1.02±0.37 vs. 1.18±0.45, P = 0.133). ③ Clinical efficacy: there was no significant difference in clinical response rate between CRRT group and non-CRRT group [68.2% (15/22) vs. 80.9% (55/68), P = 0.213]. ④ Safety: acute kidney injury occurred in 2 patients (2.9%) in the non-CRRT group. No obvious neurological symptoms and skin pigmentation were found in the two groups. Conclusions:CRRT had little effect on the elimination of colistin sulfate. Routine blood concentration monitoring (TDM) is warranted in patients received with CRRT.