Berberine delays onset of collagen induced arthritis through T cell suppression

Abstract

RUNNING TITLE (less than 50 characters): Berberine delays onset of collagen arthritis model KEY WORDS (5 words not in the title): CIA, berberine, RA, autoimmune, T cell ABSTRACT (250 words or less): Previous evidence suggests that berberine (BBR), a clinically relevant plant-derived alkaloid, alleviates symptoms of clinically apparent collagen induced arthritis (CIA), and may have a prophylactic role from in vitro studies. Thus, we used a CIA model to determine if BBR merits further exploration as a prophylactic treatment for rheumatoid arthritis. Mice were treated with either 1 mg/kg/day of BBR or a vehicle (PBS) control via IP injections from day 0 to day 28, were left untreated (CIA control), or were in a non-arthritic control group. Incidence of arthritis in BBR mice was 40%, compared to 90% in the CIA and 80% in the PBS controls. Populations of B cells and T cells from the spleens and draining lymph nodes were examined from mice across treatment groups on day 14 and from the remaining mice on day 28 when arthritic signs and symptoms were expected to be apparent. BBR-treated mice had significantly reduced populations of CD4 + T cells, CXCR5 + T fh cells, and an increased proportion of T reg at both day 14 and day 28 endpoints, as well as decreased CD28 + and CD154 + CD4 + T cells at day 14. BBR-treated mice also experienced a significant reduction of CD19 + B cells in LNs at day 28. Additionally, BBR treatment resulted in significantly lower anti-collagen type II-specific (anti-CII) IgG2a and anti-CII total IgG serum concentrations. These results indicate a potential role for BBR as a prophylactic supplement, and that its effect may be mediated through T cell suppression, which indirectly affects B cell activity. and PBS controls ( Fig. 2B). When comparing anti-CII IgG levels between arthritic and nonarthritic mice within the BBR group specifically, however, anti-CI IgG1, IgG2a and total IgG were all significantly reduced in the non-arthritic mice compared to those who developed arthritis (Fig. 2C). Additionally, there appeared to be a vehicle-specific effect on circulating anti-CII IgG in which the administration of PBS with 0.01% DMSO elicited elevated levels of anti-CII IgG1 and total IgG in vehicle control mice ( Fig. 2A-B).Key CD4 + T cell population characteristics in response to berberine treatment-On day 14, we observed a significant reduction in populations of both CD4 + T cells and CXCR5 + T fh cells in the LNs and spleen of BBR-treated mice (Fig. 3A-B), as well as a reduction in the percentage of CD28 + and CD154 + CD4 + T cells in the spleen and LNs of BBR-treated mice (Fig. 3A-B). By the day 28 experimental endpoint we continued to observe a significant reduction in CD4 + T cells and CXCR5 + T fh cells in the spleen and LNs of BBR-treated mice ( Fig. 3C-D), however, there was no significant difference in the percentage of CD28 + and CD154 + CD4 + T cells between treatment groups (Fig 3C-D). Berberine treatment leads to increased proportion of FOXP3 + CD25 + CD4 + T cells-To examineBBRs effect on ...