Bcl2L12 Contributes to Th2-Biased Inflammation in the Intestinal Mucosa by Regulating CD4+ T Cell Activities.

The Th2-biased inflammation and immune deregulation play a critical role in the pathogenesis of ulcerative colitis (UC). Recent studies indicate that the Bcl2-like protein 12 (Bcl2L12) is associated with immune deregulation of UC. This study aims to investigate the role of Bcl2L12 in the induction of aberrant Th2-biased inflammation. In this study, peripheral blood samples were collected from patients with inflammatory bowel disease. The Th2 cell activities were analyzed by flow cytometry, real-time quantitative RT-PCR, and Western blotting. Mice with Bcl2L12-knockout CD4+ T cells were used in the experiments. The results showed that the expression of Bcl2L12 was detected in peripheral CD4+ T cells, which was significantly higher in UC patients than in healthy subjects. A positive correlation between the expression of Bcl2L12 and Th2 cytokines was detected in CD4+ T cells from UC patients. Naive CD4+ T cells with Bcl2L12 overexpression were prone to differentiate into Th2 cells. Mice with Bcl2L12 deficiency failed to induce the Th2-biased inflammation in the intestine. Bcl2L12 bound GATA3 to form a complex to enhance the binding between GATA3 and the Il4 promoter to enhance the expression of IL-4 in CD4+ T cells. CD4+ T cells with Bcl2L12 overexpression were resistant to apoptosis. In conclusion, the Bcl2L12 is a critical factor in the induction of aberrant Th2 polarization by upregulating Th2 responses and downregulating Th2 cell apoptosis. Bcl2L12 may be a novel therapeutic target in the management of the disorders with Th2-biased inflammation.

Tumor necrosis factor suppresses interleukin 10 in peripheral B cells via upregulating Bcl2-like protein 12 in patients with inflammatory bowel disease.

The pathogenesis of the immune regulation dysfunction is unclear. Bcl2-like protein 12 (Bcl2L12) has immune suppression function. This study tests a hypothesis that tumor necrosis factor (TNF) increases Bcl2L12 to suppress the expression of interleukin (IL) 10 in peripheral B cells of patients with inflammatory bowel disease (IBD). In this study, peripheral blood samples were collected from IBD patients and healthy controls. B cells were isolated from the blood samples. The expression of IL-10 and Bcl2L12 in B cells was analyzed by quantitative reverse transcription polymerase chain reaction and Western blotting. We observed that the expression of Bcl2L12 in the peripheral B cells was higher in IBD patients than that in healthy controls. The IL-10 levels in B cells were negatively correlated with the expression of Bcl2L12. Exposure of B cells to TNF in the culture enhanced the expression of Bcl2L12. The Bcl2L12 mediated the effects of TNF on suppression of IL-10 in B cells. In conclusion, Bcl2L12 mediates the effects of TNF to suppress the expression of IL-10 in B cells. The data suggest that Bcl2L12 may be a therapeutic target for the treatment of IBD.

Histone deacetylase 11 inhibits interleukin 10 in B cells of subjects with allergic rhinitis.

BACKGROUND: The interleukin (IL)-10 expression in B cells plays an important role in immune tolerance. The regulation of IL-10 expression in B cells is not fully understood yet. Tumor necrosis factor (TNF) is increased in allergic rhinitis (AR) patients. This study tests a hypothesis that TNF enhances histone deacetylase (HDAC)11 expression to inhibit the expression of IL-10 in B cells of AR patients. METHODS: Peripheral B cells were collected from healthy persons and patients with AR. The B cells were analyzed by immune assay and molecular biological approaches for the expression of IL-10. RESULTS: The expression of HDAC11 was higher in B cells of patients with AR than that in healthy persons. The expression of IL-10 in B cells was lower in AR patients than that in healthy subjects. The levels of HDAC11 in B cells were negatively correlated with the levels of IL-10. Exposure of B cells to TNF in the culture inhibited the expression of IL-10, in which HDAC11 played a critical role in the interference with the Il10 gene transcription. Inhibition of HDAC11 restored the IL-10 expression in B cells from AR patients and attenuated the experimental AR. CONCLUSION: TNF can suppress the expression of IL-10 in B cells via enhancing the expression of HDAC11. Inhibition of HDAC11 restores the IL-10 expression in B cells of AR subjects. HDAC11 may be a novel target for the treatment of AR.

MicroRNA-98 plays a critical role in experimental myocarditis.

BACKGROUND AND AIMS: Myocarditis is inflammation in the heart; its pathogenesis is to be further investigated. Activities of micro RNAs (miR) are associated with immune inflammation. This study tests a hypothesis that miR-98 is involved in the development of myocarditis. METHODS: BALB/c mice were immunized with cardiac α-myosin heavy chain peptides (MyHC-α) to induce myocarditis. The effects of miR-98 on regulation of interleukin (IL)-10 were assessed by real time RT-PCR. RESULTS: Mice immunized with MyHC-α showed myocarditis and lower frequency of IL-10+ B cells (B10 cell) in the hearts. Expression of miR-98 was higher, IL-10 was lower, in B cells isolated from the mouse hearts with myocarditis, which was negatively correlated with each other. Exposure to tumor necrosis factor-α up regulated miR-98 expression in B cells. Over-expression of miR-98 suppressed IL-10 expression in B cells. Blocking miR-98 or adoptively transplanting B10 cells attenuated experimental myocarditis. CONCLUSIONS: miR-98 suppresses IL-10 expression in B cells in the heart, which plays an important role in myocarditis. MiR-98 may be a therapeutic target in the treatment of myocarditis.

Micro RNA-98 suppresses interleukin-10 in peripheral B cells in patient post-cardio transplantation.

The immune tolerance to the transplant heart survival is critical. Regulatory B cells are one of the major immune regulatory cell populations in the immune tolerance. Micro RNAs (miR) can regulate the activities of immune cells, such as the expression of interleukin (IL)-10 by B cells. This study tests a hypothesis that micro RNA (miR)-98 plays a role in the regulation of interleukin (IL)-10 expression in B cells (B10 cell) after heart transplantation. In this study, the peripheral blood samples were collected from patients before and after heart transplantation. The expression of miR-98 and IL-10 in B cells was assessed by real time RT-PCR. An allograft heart transplantation mouse model was developed. We observed that after heart transplantation, the frequency of peripheral B10 cell and the IL-10 mRNA levels in peripheral B cells were significantly decreased, the levels of miR-98 were increased in peripheral B cells and the serum levels of cortisol were increased in the patients. Treating naive B cells with cortisol in the culture suppressed the expression of IL-10 in B cells, which was abolished by knocking down the miR-98 gene. Administration with anti-miR-98, or cortisol inhibitor, or adoptive transfer with B10 cells, significantly enhanced the survival rate and time of mice received allograft heart transplantation. In conclusion, the enhancement of serum cortisol affects the immune tolerant feature of B cells, which can be attenuated by anti-miR-98-carrying liposomes.

Vitamin D3 induces vitamin D receptor and HDAC11 binding to relieve the promoter of the tight junction proteins.

Intestinal epithelial barrier dysfunction and vitamin D (VitD)-deficiency play a critical role in a large number of diseases. The histone deacetylases (HDAC) are associated with a large number of immune diseases. This study tests a hypothesis that the interaction between VitD and HDAC is associated with the regulation of epithelial barrier functions. In this study, human intestinal epithelial cell line, T84 cells, was cultured into monolayers to be used as a model to test the epithelial barrier functions. We observed that in a VitD-deficient environment, the T84 monolayer barrier function was compromised. Exposure to calcitriol (the active form of VitD3) in the culture increased the expression of VitD receptor (VDR) in T84 cells. In a VitD-sufficient environment, VDR formed a complex with histone deacetylase-11 (HDAC11); the complex was markedly decreased in a VitD-deficient environment. We also observed that significantly more binding of HDAC11 to the promoter of the tight junction proteins inhibit the gene transcription activities of these loci in the VitD-deficient environment, which were abolished by the presence of calcitriol in the culture. In conclusion, the interaction between VDR and HDAC11 plays a crucial role in the maintenance of the epithelial barrier integrity.

[Effect of n-3 polyunsaturated fatty acids on proliferation and apoptosis of human colon cancer cell].

OBJECTIVE: To investigate the effects of n-3 polyunsaturated fatty acids(n-3PUFA) on human colorectal cancer cell line HT-29 and associated mechanism. METHODS: The effects of docosahexaenoic acid (DHA) on the proliferation and apoptosis on HT-29 human colorectal cancer cells were evaluated by MTT assay, cell morphology (Hoechst33258 dyeing), DNA gel electrophoresis, and flow cytometry. The content of n-6PUFA and n-3PUFA of the treated cells and the ratio of n-6/n-3PUFA were analyzed by chromatography. RESULTS: DHA effectively inhibited HT-29 cell proliferation in a dose- and time-dependent manner. The proliferative inhibition rates of HT-29 cells treated with 10, 20, 40, and 80 mg/L DHA for 24 hours were 16.8%, 24.7%, 50.0%, and 60.1%, respectively, while the inhibition rates were 50.0%, 69.9%, and 77.0% respectively when HT-29 cells were treated with 40 mg/L DHA for 24, 48, and 72 hours. The typical apoptotic morphologic changes of HT-29 cells could be observed, including chromatin margination, nuclear condensation and apoptotic bodies. Gel electrophoresis of DNA degradation displayed typical DNA ladder fragments. HT-29 cells treated with DHA were arrested in G1 phase and the proportion of HT-29 cells in Gl phase increased compared with that of the control group (72.1% vs. 51.3%) while the proportion of the cells in S phase decreased significantly (19.9% vs. 38.9%). The content of n-6PUFA decreased, n-3PUFA content increased and the ratio of n-6/n-3PUFA lowered significantly in colorectal cancer cells treated with DHA (P<0.01). CONCLUSIONS: n-3PUFA can inhibit the growth of human colorectal cancer cells via inhibition of the proliferation and induction of apoptosis. These effects may be associated with decrease in n-6/n-3PUFA ratio.