Shan-shan Song

BAFF/BAFF-R involved in antibodies production of rats with collagen-induced arthritis via PI3K-Akt-mTOR signaling and the regulation of paeoniflorin

ETHNOPHARMACOLOGICAL RELEVANCE Paeoniflorin (Pae) is extracted from the root of paeonia lactiflora which have attracted attention for anti-rheumatic and immune modulating properties. AIM OF THE STUDY To investigate the role of PI3K/Akt/mTOR signaling mediated by BAFF/BAFF-R in antibodies production and the regulation of Pae on the signaling pathway in rats with collagen-induced arthritis (CIA). MATERIALS AND METHODS CIA rats were randomly separated into different groups and treated with Pae (25, 100mg/kg) from day 18 to day 38 after immunization. The effects of Pae on B lymphocytes of CIA rats were evaluated by the levels of BAFF, anti-CII antibody, IgA, IgG and IgM, and the expressions of BAFF-R, PI3K, p-Akt and mTOR. RESULTS In CIA rats, the levels of anti-CII antibody, IgA, IgG and IgM in serum enhanced, BAFF, BAFF-R, PI3K, p-Akt and mTOR were highly expressed. Pae (100mg/kg) obviously decreased arthritis score, relieved ankle and paw swelling, improved spleen histopathology in CIA rats, decreased the levels of IgA, IgM, IgG and anti-CII antibody, and significantly decreased the expressions of BAFF, BAFF-R, PI3K, p-Akt and mTOR. CONCLUSION PI3K/Akt/mTOR signaling mediated by BAFF/BAFF-R participates in antibodies production by B lymphocytes of CIA rats. Pae had therapeutic effects on rats with CIA. These effects might be relative to regulating PI3K/Akt/mTOR signal mediated by BAFF/BAFF-R, and down regulate the antibodies production further.

Pro-apoptotic effect of epigallo-catechin-3-gallate on B lymphocytes through regulating BAFF/PI3K/Akt/mTOR signaling in rats with collagen-induced arthritis.

To investigate the role of PI3K/Akt/mTOR signaling mediated by B cell-activating factor belonging to the TNF family (BAFF) involved in anti-apoptosis of B lymphocytes in rats with collagen-induced arthritis (CIA) and the regulation of epigallo-catechin-3-gallate (EGCG). Sprague-Dawley rats were immunized to induce CIA. CIA rats were randomly separated into different groups and treated with EGCG (40, 80 mg/kg), Paeoniflorin (100mg/kg) from day 18 to day 38 after immunization. The effects of EGCG on B lymphocytes were evaluated by the levels of BAFF, anti-CII antibody, IgA, IgG and IgM, and the expressions of BAFF receptor, P110δ, p-Akt, mTORC1, Bcl-xL and Bim. B lymphocyte proliferations were analyzed by MTT assay. Apoptosis of B lymphocyte were assayed by flow cytometry. Results showed that, in CIA rats, the levels of BAFF, anti-CII antibody, IgA, IgG and IgM enhanced. BAFF receptor, P110δ, p-AKT, mTORC1 and Bcl-xL were expressed highly, while Bim expression decreased. EGCG (40, 80 mg/kg) and Paeoniflorin decreased the levels of BAFF, anti-CII antibody, IgA, IgG, IgM and the expressions of BAFF receptor, P110δ, p-AKT, mTORC1, Bcl-xL in CIA rats, and increased Bim expression. Further studies showed that EGCG could reduce the expression of P110δ and mTORC1 in vitro. EGCG inhibited B lymphocyte proliferation and induced B lymphocyte apoptosis. In conclusion, BAFF/BAFF receptor might regulate B cell anti-apoptosis through PI3K/Akt/mTOR pathway. EGCG had therapeutic effects on CIA rats, which might be relative to the inhibition effects of EGCG on BAFF and PI3K/Akt/mTOR signaling, and then the apoptosis of B lymphocytes was promoted further.

BF02, a recombinant TNFR2 fusion protein, alleviates adjuvant arthritis by regulating T lymphocytes in rats

Aim:To investigate the therapeutic effects of BF02 on adjuvant arthritis (AA) in rats and the regulatory effects of BF02 on T lymphocyte function.Methods:SD rats received a single intradermal injection of Freunds complete adjuvant emulsion into the right hind metatarsal footpad. After the onset of AA, the rats were injected BF02 (1, 3, or 9 mg/kg, sc) every 3 d for a total of 15 d. Intragastric administration of methotrexate (MTX, 0.5 mg/kg, every 3 d for a total of 15 d) was taken as the positive control drug. Arthritis index, swollen joint count, ankle joint histopathology, spleen histopathology and the paw radiography were used for evaluating the drug effects on AA rats. T lymphocyte function was assessed by measuring T lymphocyte cytokine levels, IL17 and TNF-α mRNA expression levels, and percentage of T lymphocyte subsets.Results:In the AA rats, remarkable secondary inflammatory responses exhibited, accompanied by significantly higher levels of IL-1, IL-6, TNF-α, IL-17, LTα, RANKL, and MMP-13. The expression of IL17 and TNF-α mRNAs was also substantially higher than in normal rats. The percentages of CD3+CD4+ and CD4+CD25+ T lymphocytes were increased, whereas the percentages of CD4+CD62L+ and CD4+CD25+FoxP3+ T lymphocytes were decreased. Treatment of the AA rats with BF02 (9 mg/kg) or MTX significantly decreased the arthritis index, swollen joint count and arthritis global assessment. Moreover, both BF02 (9 mg/kg) and MTX significantly inhibited T lymphocyte proliferation, and blocked the above mentioned aberrance in T lymphocyte cytokine levels, IL17 and TNF-α mRNA expression, and percentages of T lymphocyte subsets.Conclusion:BF02 exerts therapeutic effects on AA rats via the regulation of T lymphocytes.

Bone marrow CD11b+F4/80+ dendritic cells ameliorate collagen-induced arthritis through modulating the balance between Treg and Th17

Tolerogenic dendritic cells (DCs) are well-known to show an immunosuppressive function. In this study we determine the therapeutic effects and potential mechanisms of transferred bone marrow (BM) CD11b(+)F4/80(+) DCs on collagen-induced arthritis (CIA) in mice. Murine BM CD11b(+)F4/80(+) DCs were generated under the stimulation of GM-CSF and IL-4, and the function of BM CD11b(+) F4/80(+) DCs was identified by measuring the levels of IL-10, TGF-beta and indoleamine 2,3-dioxygenase (IDO). BM CD11b(+)F4/80(+) DCs were transferred to CIA mice by intravenous injections. The histopathology of joint and spleen were evaluated. T lymphocyte proliferation, Treg and Th17 subsets were analyzed. The expressions of Foxp3, Helios and RORγt in T lymphocytes co-cultured with BM CD11b(+)F4/80(+) DCs were measured in vitro. We found that BM CD11b(+)F4/80(+) DCs induced by GM-CSF and IL-4 could express high levels of IL-10, TGF-beta and IDO. BM CD11b(+)F4/80(+) DCs significantly reduced the pathologic scores in joints and spleens, which correlated significantly with the reduced T lymphocyte proliferation and Th17 cell number, and with the increased Tregs number. In vitro, OVA-pulsed BM CD11b(+)F4/80(+) DCs promoted Treg cell expansion, enhanced IL-10 and CTLA-4 protein expression, augmented Foxp3 and Helios mRNA expression, and inhibited RORγt and IL-17 mRNA expression. Taken together, BM CD11b(+)F4/80(+) DCs are able to ameliorate the development and severity of CIA, at least partly by inducing Foxp3(+) Treg cell expansion and suppressing Th17 function. The BM CD11b(+)F4/80(+) DCs might have a promising immunotherapeutic potential for autoimmune arthritis.

Etanercept attenuates collagen-induced arthritis by modulating the association between BAFFR expression and the production of splenic memory B cells

Anti-tumour necrosis factor-α (TNF-α) drugs are approved for the treatment of rheumatoid arthritis (RA). Many studies have investigated the effect of these drugs on the T cell response; however, some clues have indicated that it may also target B cells. This study was carried out to explore the potential effects and mechanisms of etanercept, a soluble TNF-α receptor, on the function of B cells and their development into memory B cells in type II collagen (CII)-induced arthritis (CIA). Beginning on day 24 after CII immunisation, the mice were evaluated every 2-3 days to determine two clinical parameters: their arthritis global assessment and swollen joint count (SJC). The serum concentrations of IgG1, IgG2a and anti-CII antibodies and the splenic pathology and proliferation of B cells were measured. The percentage of total memory B cells in the spleen was analysed with flow cytometry. BAFFR was detected by immunohistochemistry. In CIA mice, etanercept markedly suppressed the arthritis global assessment and the SJC, reduced the production of anti-CII, IgG1 and IgG2a antibodies, and prevented spleen histopathology to varying degrees; however, it had no obvious effect on splenic B cell proliferation. Etanercept also decreased the percentage of total CD27(+) memory B cells in the spleen. Treatment with etanercept was associated with a further increase in BAFFR expression, a significant reduction in CD27 expression, and a negative correlation between the levels of BAFFR and the percentage of memory B cells. Our findings showed that increased BAFFR expression has a regulatory effect on the activation of B cells and the generation of memory B cells, which may be one of the mechanisms of the therapeutic effects of etanercept.

Comparative efficacy of TACI-Ig with TNF-alpha inhibitor and methotrexate in DBA/1 mice with collagen-induced arthritis.

The efficacies of TACI-Ig, rhTNFR:Fc and Methotrexate were compared in collagen-induced arthritis (CIA) mice. Sixty animals were divided into six groups: TACI-Ig (9 mg/kg), rhTNFR:Fc (4 mg/kg), Methotrexate (2mg/kg) and IgG-Fc (9 mg/kg) groups and were given medication for six weeks. Meanwhile, normal and CIA mice were given as control. The different efficacies of drugs were evaluated by the analyses of ankle joints and spleens pathology, cytokines, T and B lymphocytes subsets. TACI-Ig and rhTNFR:Fc reduced arthritis scores seven days later than that of Methotrexate. TACI-Ig and Methotrexate were superior to rhTNFR:Fc in reduction synovial hyperplasia and cell infiltration scores. The same result was observed for scores of spleens histopathology. TACI-Ig and Methotrexate presented higher efficacy than rhTNFR:Fc on B lymphocyte stimulator, but TACI-Ig was inferior to rhTNFR:Fc on TNF-alpha. TACI-Ig and Methotrexate could reduce significantly IgA and IgM, but rhTNFR:Fc had no effects on these immunoglobulins. TACI-Ig had more efficacy than rhTNFR:Fc in the decrease of CD4(+)CD154(+) T cell. TACI-Ig and Methotrexate also reduced CD4(+)CD69(+) T cell, rhTNFR:Fc had no effects on the T cell subset. TACI-Ig and Methotrexate were superior to rhTNFR:Fc on CD4(+)CD62L(+)T cells. TACI-Ig and Methotrexate could reduce CD19(+)IgD(+) and CD19(+)CD21(+) B cells, but rhTNFR:Fc had no obvious effect on above B cells subsets. TACI-Ig is as effective as rhTNFR:Fc and Methotrexate on CIA mice by ameliorating joint and spleen pathology, regulating T and B lymphocytes function, although different mechanisms among them. This study would be useful for treatment selection of rheumatoid arthritis in different pathological conditions.

Effect of bone marrow-derived CD11b+F4/80+ immature dendritic cells on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis

ObjectiveTo explore the effect of bone marrow-derived CD11b+F4/80+ immature dendritic cells (BM CD11b+F4/80+iDC) on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis (CIA).MethodsBM CD11b+F4/80+iDC were induced with rmGM-CSF and rmIL-4, and were identified by the expressions of toll-like receptor 2 (TLR-2), indoleamine 2,3-deoxygenase (IDO), interleukin (IL)-10, transforming growth factor (TGF)-β1 and mixed leukocyte reaction (MLR). CIA was established in DBA/1 mice by immunization with type II collagen. CIA mice were injected intravenously with BM CD11b+F4/80+iDC three times after immunization. The effect of BM CD11b+F4/80+iDC on CIA was evaluated by the arthritis index, joint histopathology, body weight, thymus index, thymocytes proliferation, IL-1β, tumor necrosis factor (TNF)-α, IL-17, IL-10 and TGF-β1 levels.ResultsBM CD11b+F4/80+iDC induced with rmGM-CSF and rmIL-4 expressed high levels of TLR-2, IDO, IL-10 and TGF-β1. Infusion of BM CD11b+F4/80+iDC in CIA mice significantly reduced the arthritis index and pathological scores of joints, recovered the weight, decreased the thymus index and inhibited thymocyte proliferation. Levels of IL-1β, TNF-α and IL-17 were decreased in BM CD11b+F4/80+iDC-treated mice.ConclusionsBM CD11b+F4/80+iDC can be induced successfully with rmGM-CSF and rmIL-4. BM CD11b+F4/80+iDC treatment can ameliorate the development and severity of CIA by regulating the balance between pro-inflammatory cytokines and anti-inflammatory cytokines.

BAFF upregulates CD28/B7 and CD40/CD154 expression and promotes mouse T and B cell interaction in vitro via BAFF receptor.

Aim:B cell-activating factor belonging to the TNF family (BAFF) is a member of TNF family and required for peripheral B cell survival and homeostasis. BAFF has been shown to promote the proliferation of T and B cells. In this study we examined whether and how BAFF mediated the interaction between mouse T and B cells in vitro.Methods:BAFF-stimulated B or T cells were co-cultured with T or B cells. The interactions between T and B cells were analyzed by measuring the expression of co-stimulatory molecules (CD28/CD80 or CD40/CD154), the proliferation and secretion of T and B cells and other factors. Two siRNAs against the transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) and BAFF receptor (BAFF-R) were used to identify the receptors responsible for the actions of BAFF.Results:BAFF-stimulated B cells significantly promoted the proliferation and activity of co-cultured T cells, and increased the percentages of CD4+CD28+ and CD4+CD154+ T cells. Similarly, BAFF-stimulated T cells significantly promoted the proliferation and activity of co-cultured B cells, and increased CD19+CD80+ and CD19+CD40+B cell subpopulations. BAFF-R siRNA-silenced B cells showed significantly lower expression of CD40 and CD80 than the control B cells. When the BAFF-R siRNA-silenced B cells were stimulated with BAFF, then co-cultured with T cells, the expression of CD28 and CD154 on T cells was not increased. TACI siRNA-silenced B cells exhibited higher expression of CD40 and CD80 than the control B cells. When the TACI siRNA-silenced B cells were stimulated with BAFF, then co-cultured with T cells, the expression of CD28 and CD154 on T cells was significantly increased.Conclusion:BAFF upregulates CD28/B7 and CD40/CD154 expression, and promotes the interactions between T and B cells in a BAFF-R-dependent manner.