Novel Immunomodulatory Properties of Berbamine through Selective Down-Regulation of STAT4 and Action of IFN-γ in Experimental Autoimmune Encephalomyelitis

Abstract

Berbamine (BM) is an herbal compound derived from Berberis vulgaris L commonly used in traditional Chinese medicine. In this study, we show that BM has potent anti-inflammatory properties through novel regulatory mechanisms, leading to reduced encephalitogenic T cell responses and amelioration of experimental autoimmune encephalomyelitis (EAE). The treatment effect of BM was attributable to its selective inhibitory effect on the production and action of IFN-γ in CD4+ T cells, which was mediated through altered STAT4 expression in T cells. BM was found to up-regulate SLIM, a ubiquitin E3 ligase for STAT4, and promote STAT4 degradation, resulting in markedly decreased IFN-γ production in CD4+ T cells in EAE mice. Regulation of IFN-γ by BM had profound anti-inflammatory actions through its effect on both CD4+ T cells and APCs. BM-treated APCs exhibited reduced stimulatory function as a result of altered expression of PD-L1, CD80, and CD86 in treated mice. The treatment effect of BM in EAE was directly related to its action on IFN-γ, and was abolished in IFN-γ knockout mice. The study also confirmed that BM was able to inhibit NFAT translocation through effecting calcium mobilization in lymphocytes. However, this effect was not directly responsible for the treatment efficacy of BM in EAE. The study has important implications in our approaches to evaluating the utility of natural compounds in drug discovery and to probing the role of cytokine network in the development of autoimmune conditions.

Berberine Differentially Modulates the Activities of ERK, p38 MAPK, and JNK to Suppress Th17 and Th1 T Cell Differentiation in Type 1 Diabetic Mice

“…Ren et al (32) found that berbamine targets STAT4 via a ubiquitinprotein isopeptide ligase resulting in decreased production of IFN␥ in CD4 ϩ T cells of experimental autoimmune encephalomyelitis mice, whereas the secretion of IL-17 was not markedly altered. In our study, berberine inhibited the production of both IFN␥ and IL-17 in NOD mice probably as a result of structural differences between berberine and berbamine.…”

“…Berberine Significantly Decreases the Production of Inflammatory Cytokines in NOD Mice-Previous studies have indicated that the administration of berberine up-regulates the expression of IL-10 (25) and down-regulates inflammatory cytokines, including IFN␥, TNF␣, and IL-1␤, but had limited effect on IL-17 production (23,24,27,32) in various animal models. To examine whether berberine affected the cytokine profile in this murine model of type 1 diabetes, splenocytes were isolated from vehicle-or berberine-treated NOD mice and were stimulated with ␣-CD3 antibody at the indicated concentration for 48 h. The cytokine profile of the supernatant showed a dramatic decrease in inflammatory cytokines, including IL-17, IL-6, IFN␥, and TNF␣ (Fig.…”

Epigallocatechin-3-Gallate Ameliorates Experimental Autoimmune Encephalomyelitis by Altering Balance among CD4+ T-Cell Subsets

“…Furthermore, Th17 cells are implicated in this model and in several other autoimmune diseases. Although some autoimmune responses formerly attributed to Th1 cells are now believed to be mediated by Th17 cells, recent studies [5][6][7][8][9] continue to emphasize the importance of Th1 cells in EAE development. In fact, EAE can be induced by transfer of either Th17 or Th1 cells.…”

Regulation of Th1 and Th17 Cell Differentiation and Amelioration of Experimental Autoimmune Encephalomyelitis by Natural Product Compound Berberine

“…Cells were directly lysed in SDS sample buffer, and Western blot analysis was conducted as previously described (38). Abs were purchased from Cell Signaling Technology (Beverly, MA).…”