The Pro-apoptotic Effects Of Berberine On Mouse Bone Marrow Derived Dendritic Cells

Berberine (Ber) is an isoquinoline alkaloid present in numerous plants, is widely considered to be no cytotoxic and mutagenic effects, with a wide range of drug use. It has been used as a heat-clearing and detoxifying drugs and antibacterial agents in clinical for many years,with multifaceted pharmacological effects,such as anti-tumor hypoglycemic etc. Scientistsinitially identified berberine has a strong anti-inflammatory and immunesuppressing properties with the continuous deepening of the study in Ber. Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that initiate lymphocyte activation and may also be critical for maintaining immune tolerance[1,2].It is believed that the maturation state of DCs might be an important control point for the immune modulation which can decide the development of immune response[4,5]. Thus, both maturity level and longevity of DCs must be tightly regulated to ensure the proper functioning of adaptive immunity and avoid autoimmunity. Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disorder with a heterogeneous course. DCs are thought to play an important role in driving immunopathogenic responses that lead to the establishment of chronic proliferative synovitis and joint destruction in RA[10-14]. Accordantly, recent accumulating evidence indicates that many classical immunosuppressive agents such as corticosteroids, cyclosporine A, rapamycin, and 1,25(OH)2D3, whose immunosuppressive effects have been ascribed for a long time mainly to the suppression of T-cell activation, interfere with immune responses by targeting key functions of DCs or evoking DC apoptosis [15-18] . Therefore, DCs might be an important target for immunosuppressive therapy of RA. It is regrettable that currently drugs for the treatment of autoimmune diseases clinical use is severely hampered due to their toxicity side effects.In view of a wide range of anti-inflammatory immunosuppressive properties and non-toxic side-effects of berberine ,there is also no reports to the impact of berberine on DC or the RA so far yet, this topic is intended to berberine a potential drug for the treatment of rheumatoid arthritis,we carried out the following research: To investigate whether berberine (Ber), a natural compound derived from plants used traditionally in Chinese medicine, selectively induces apoptosis in dendritic cells (DCs) and has therapeutic potential for rheumatic arthritis.The results are showed as follow:Vitro:(1) In vitro apoptosis induced by Ber in murine bone marrow-derived DCs (BMDCs), peritoneal macrophages, Raw264.7 cells, Jurkat T cells, and different types of cancer cells was determined by assays of phosphatidylserine exposure, as well as morphologic nuclear changes, the loss of mitochondrial membrane potential, ROS generation, and cell cycle progression in some experiments. The results show that addition of Ber (2-50μM) in bone marrow cell culture reduced DC recovery by inducing cell apoptosis. The sensitivity to Ber-induced apoptosis was acquired from day 3 onward of BMDC differentiation, and mature DCs were more sensitive for Ber-induced apoptosis than immature DC. Freshly isolated mouse bone marrow cells, peritoneal macrophages, Raw264.7, and Jurkat cells were insensitive for Ber-induced apoptosis. Although Ber exhibited pro-apoptotic effects on some cancer cells, DCs appear to be more sensitive to Ber-induced apoptosis than cancer cells tested.Vivo:(2) The in vivo effects of Ber were examined in a murine model of type II bovine collagen (CII)-induced arthritis (CIA). The immune responses against CII were determined by assays of serum antibody levels, lymphocyte proliferation, and cytokine production. The numbers and apoptosis of DCs in spleens or draining lymph nodes (LNs) were analyzed by flow cytometry and immunohistochemistry after DC markers and TUNEL staining. The results show that in CIA mice, the intraperitoneal administration of Ber reduced the incidence and severity of arthritis, the anti-CII antibody levels, lymphocyte proliferation, and production of IFN-γand IL-17 from splenocytes in response to CII stimulation. Moreover, Ber markedly reduced DC numbers in spleens and draining LNs and increased incidence of apoptosis among DCs.In Conclusion, Ber selectively induces apoptosis in mature DCs and exhibit anti-arthritic and immunosuppressive properties in CIA mice.