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Objective:To investigate the regulatory effects and mechanism of mannose-binding lectin(MBL) on autophagy during the differentiation of 3T3-L1 adipocytes, and provide the feasibility for targeting autophagy to prevent obesity and related pathological conditions in natural immunity.Methods:3T3-L1 preadipocytes were cultured in vitro and induced to differentiation. Cell differentiation and lipid accumulation were analyzed by oil red O staining and CCK-8 was used to detect the effect of different concentrations of MBL (0, 1, 5, 10 μg/ml) on cell proliferation ability at different differentiation stages. Western blot was used to analyze the expression of MBL(10 μg/ml) on the key autophagy factors LC3B, Beclin1 and p62 protein at different stages of differentiation, and the changes of lipid droplet accumulation under the intervention of MBL were observed by oil red O staining. The protein and mRNA expression of autophagy key factors under the intervention of different concentrations of MBL were detected by Western blot and qRT-PCR. And autophagy flow analysis based on autophagic degradation was used to further illustrate the autophagic activity. The expression and phosphorylation of adenosine monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR) signaling molecules were analyzed by Western blot. Results:The results of oil red O staining showed that 3T3-L1 preadipocytes could achieve complete differentiation after 10 days of induction. CCK-8 showed that the concentration of MBL (1-10 μg/ml) in the experimental group had no effect on cell proliferation at different differentiation stages. During the differentiation of 3T3-L1 preadipocytes, Western blot and qRT-PCR showed that the expression of autophagy-related proteins and mRNA levels was enhanced in the MBL treated group, and presented a concentration-dependent relationship. Oil red O staining showed that the lipid droplets in adipocytes at different stages of differentiation are reduced to varying degrees under the intervention of MBL. Fluorescence microscopy results further confirmed that MBL enhanced the autophagy activity of adipocytes by increasing the synthesis of autophagosomes. Moreover, under the intervention of MBL, the phosphorylation level of AMPK was significantly up-regulated, while the phosphorylation level of mTOR was significantly down-regulated, also showing a concentration-dependent relationship.Conclusions:MBL accelerates the autophagy process during the differentiation of 3T3-L1 adipocytes through AMPK/mTOR signaling pathway, reduces lipid accumulation, providing a possible functional pathway for the treatment of obesity and related metabolic diseases.
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Objective:To investigate the regulatory effects and mechanism of mannan-binding lectin (MBL) on adipogenic differentiation of 3T3-L1 preadipocytes.Methods:3T3-L1 preadipocytes were induced to differentiate into adipocytes in vitro, and stimulated with different concentrations of MBL (0, 1, 10, 20 μg/ml). Firstly, changes in cell proliferation ability were detected by CCK-8. Then lipid accumulation was analyzed by Oil red O staining and intracellular triglyceride content determination. Further, the expression of adipogenic differentiation-related factors PPARγ and C/EBPα at protein and mRNA levels were detected by Western blot and qRT-PCR, respectively. Finally, Western blot was used to analyze the expression and phosphorylation of Akt, a signal molecule related to adipogenic differentiation. Results:MBL at the concentrations of 0, 1, 10 and 20 μg/ml had no effect on the proliferation of 3T3-L1 preadipocytes. The level of triglyceride in MBL treatment groups decreased in a dose-dependent manner on 3 d after 3T3-L1 preadipocyte differentiation. Results of Oil red O staining showed that the number of lipid droplets in MBL treatment groups reduced significantly, and the absorbance values also decreased significantly in a concentration-dependent manner. Western blot and qRT-PCR results showed that the expression of PPARγ and C/EBPα at both protein and mRNA levels in MBL treatment groups decreased significantly in a dose-dependent manner, and the phosphorylation level of Akt was significantly down-regulated as well.Conclusions:MBL regulates the adipogenic differentiation of 3T3-L1 preadipocytes via Akt signaling pathway.
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Objective To investigate the regulation of Treg/Th17 axis by mannan-binding lectin (MBL) in mice with Candida albicans ( C. albicans ) infection. -ethods MBL gene-knockdown (MBL-/-) C57BL/6 mice and wild-type (WT) C57BL/6 mice were divided into four groups. C. albicans strains (2×107 CFU) were injected intraperitoneally into the mice of infection groups. Paraffin sections of mouse liver and kidney tissues were prepared on 3 d. Histopathological changes were observed with hematox-ylin and eosin ( HE) and Periodic acid-Schiff ( PAS) staining. Flow cytometry was performed to analyze Th17 and Treg cells in mice on 7 d. The levels of IL-10 and IL-17A were measured by ELISA. CD4+T cells were obtained from spleen cells by magnetic sorting. Expression of Foxp3 and RORγt at mRNA and protein levels were detected by qRT-PCR and Western blot, respectively. Results The mouse model of C. albicans infection was established successfully. After infection, the MBL-/- mice had higher percentages of Th17 cells, but lower percentages of Treg cells than the WT mice. ELISA results showed that compared with the WT mice with C. albicans infection, the MBL-/- mice had significantly increased IL-17A and decreased IL-10 after infection. Moreover, the expression of RORγt at both mRNA and protein levels was up-regula-ted, while that of Foxp3 was down-regulated in the MBL-/- mice than in the WT mice following infection. Conclusions MBL regulates the immune balance of Treg/Th17 cells in mice infected with C. albicans through promoting the differentiation of CD4+ T cells into Treg cell subsets and inhibiting the differentiation into Th17 cell subsets.
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Sonic Hedgehog (SHH) signaling pathway participates in the regulation of various organs and growth of tissue cells, maintains normal function and structure in the development of embryogenesis, however, SHH signaling pathway is in a state of inhibition. Meanwhile, the abnormal regulation of SHH signaling pathway plays an important role in the occurrence, development and drug resistance of leukemia. The mechanism of SHH signaling pathway in leukemia is similar to the solid tumor. With the further understanding of SHH signaling pathway, there are many antitumor drugs targeting SHH signaling pathway. The targeting inhibitors targeted SHH signaling pathway will become a new method for the treatment of leukemia. This paper reviews the application of the inhibitors targeting SHH signaling pathway in leukemia.
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Objective To investigate the effects of mannan-binding lectin ( MBL) on the differen-tiation of Th17 cells (T helper cell 17, Th17). Methods CD4+T cells were separated in vitro from fresh human cord blood by MACS ( magnetic-activated cell sorting ) separator. Anti-CD3 monoclonal antibody ( McAb) and anti-CD28 McAb were used to stimulate CD4+T cells with IL-6 and TGF-β1 as inducers. Then, these cells were treated with ( MBL group) or without ( control group) different concentrations of MBL. Percentages of Th17 cells in different groups were detected by fluorescence-activated cell sorting( FACS) after 72 hours of culturing. Quantitative real-time PCR ( Q-PCR) was used to analyze the expres-sion of RORγt ( retinoid-related orphan receptor-γ-t) at mRNA level in both control and MBL groups. En-zyme-linked immunosorbent assay (ELISA) was performed to detect the levels of IL-17A in supernatants of cell culture from different groups. FACS was used to detect the percentages of Th17 cells in MBL-/-and wild type ( WT) mice. Results MBL could significantly reduce the percentage of Th17 cells after 72 hours of culturing as compared with the control group. Moreover, MBL could significantly down-regulate the expres-sion of RORγt at mRNA level and decrease the expression of IL-17A. Results of animal experiments showed that the percentages of CD4+RORγt+Th17 cells in MBL-/- mice were significantly higher than those in WT mice. Conclusion MBL can inhibit the differentiation of CD4+T cells to Th17 cells, which is induced by IL-6 and TGF-β1.
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Objective To investigate the effects of mannan-binding lectin ( MBL) on the differen-tiation of Th17 cells (T helper cell 17, Th17). Methods CD4+T cells were separated in vitro from fresh human cord blood by MACS ( magnetic-activated cell sorting ) separator. Anti-CD3 monoclonal antibody ( McAb) and anti-CD28 McAb were used to stimulate CD4+T cells with IL-6 and TGF-β1 as inducers. Then, these cells were treated with ( MBL group) or without ( control group) different concentrations of MBL. Percentages of Th17 cells in different groups were detected by fluorescence-activated cell sorting( FACS) after 72 hours of culturing. Quantitative real-time PCR ( Q-PCR) was used to analyze the expres-sion of RORγt ( retinoid-related orphan receptor-γ-t) at mRNA level in both control and MBL groups. En-zyme-linked immunosorbent assay (ELISA) was performed to detect the levels of IL-17A in supernatants of cell culture from different groups. FACS was used to detect the percentages of Th17 cells in MBL-/-and wild type ( WT) mice. Results MBL could significantly reduce the percentage of Th17 cells after 72 hours of culturing as compared with the control group. Moreover, MBL could significantly down-regulate the expres-sion of RORγt at mRNA level and decrease the expression of IL-17A. Results of animal experiments showed that the percentages of CD4+RORγt+Th17 cells in MBL-/- mice were significantly higher than those in WT mice. Conclusion MBL can inhibit the differentiation of CD4+T cells to Th17 cells, which is induced by IL-6 and TGF-β1.
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Objective To investigate the effects of mannan-binding lectin(MBL) on TNF-α production induced by peptidoglycan (PGN) and its mechanism in human THP-1/CD14 monocytes.Methods The THP-1/CD14 cells were stimulated for 24 h with PGN at the indicated ratios after pretreated with human natural MBL at concentrations ranging from 1 to 20 mg/L for 2 h.The content of TNF-α and IL-6 in culture supernatants were detected by ELISA,and the levels of TNF-α and IL-6 mRNA expressions in these cells were determined by RT-PCR.FACS was used to investigate the interaction of MBL with THP-1/CD14 cells and the impact of MBL on PGN binding to THP-1/CD14 cells.Western blot was used to detect PGN-induced NF-κB translocation in THP-1/CD14 cells.Results ELISA showed that secretion of TNF-α and IL-6 from THP-1/CD14 cells could be induced by PGN ;The productions of TNF-α and IL-6 by THP-1/CD14 cells induced with PGN were profoundly inhibited by MBL at higher concentrations (10-20 mg/L) but not MBL at lower concentrations (1 mg/L).RT-PCR analysis also indicated that the mRNA expressions of TNF-α and IL-6 in THP-1/CD14 cells were decreased by MBL at higher concentration,compared to the corresponding THP-1/CD14 cells stimulated with PGN only.FACS showed that the binding of MBL to THP-1/CD14 cells was evident in a Ca2+-dependent manner.PGN could competitively inhibit the binding of MBL to THP-1/CD14 cells.MBL could competitively inhibit the binding of PGN to THP-1/CD14 cells by binding to THP-1/CD14 cells directly.Similarly,MBL at higher concentration (20 mg/L) decreased the NF-κB translocation in THP-1/CD14 cells.Conclusion MBL may inhibit TNF-α and IL-6 production induced by PGN in THP-1/CD14 cells through NF-κB signaling pathways,suggesting that MBL can play some roles in the regulation of PGN-induced inflammatory response.
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Objective To investigate the effects of mannan-binding lectin (MBL) on IL-8 and TNF-α production induced by Candida albicans ( C. albicans) in human THP1/CD14 monocytes. Methods The THP1/CD14 cells were stimulated for 24 h with heat-inactivated yeast form or hyphal form cells of C. albicans strain at the indicated ratios after pretreated with human natural MBL at concentrations ranging from 1 to 20 mg/L for 2 h. The content of IL-8 and TNF-α in culture supernatants were detected by ELISA,and the levels of IL-8 and TNF-α mRNA expressions in these cells were determined by RT-PCR. Western blot was used to detect C. albicans-induced NF-κB translocation in THP1/CDI4 cells. Results ELISA showed that secretion of IL-8 and TNF-α from THP1/CD14 cells could be induced by both yeast cells and hyphal cells. Hyphal cells proved to be much less efficient than yeast cells in stimulating production of IL-8and TNF-α by THP1/CD14 cells. The productions of IL-8 and TNF-α by THP1/CD14 cells induced with C.albicans were profoundly inhibited by MBL at higher concentrations ( 10-20 mg/L) but not MBL at lower concentrations ( 1 mg/L). RT-PCR analysis also indicated that the mRNA expressions of IL-8 and TNF-αt in THP1/CD14 cells were decreased to various extents by MBL at higher concentration, compared to the corresponding THP1/CD14 cells stimulated with C. albicans only. Similarly, MBL at higher concentration ( 20mg/L) decreased the NF-κB translocation in THP1/CD14 cells. Conclusion MBL may inhibit IL-8 and TNF-α production induced by dimorphism C. albicans in THP1/CD14 cells, suggesting that MBL can play some roles on the regulation of C. albicans immune response.