Comparative efficacy of Naringenin and Sinomenine in facilitating the differentiation of mouse hematopoietic stem cells into immature dendritic cells to promote transplantation immunological regulation.

OBJECTIVE: Immature dendritic cells (imDC) are crucial in facilitating transplant immunological regulation. However, imDC is readily amenable to maturation. Sinomenine (Sin) naringin (Nar) are traditional Chinese medicine with immunoregulation and anti-inflammatory activities. We investigated the effect of Sin and Nar on the generation of immature dendritic cells (imDC) and their ability to prolong the survival of skin allografts in mice.

METHODS: Hematopoietic stem cells (HSC) obtained from bone marrow prompted to develop into immature dendritic cells (imDC) through treatment with Sin (Sin-HSC-imDC) or Nar (Nar-HSC-imDC). The cell counting kit-8 (CCK-8) assay was employed to assess the differentiating efficacy of Sin-HSC-imDC and Nar-HSC-imDC. DC surface markers and apoptosis following lipopolysaccharide (LPS) treatment were assessed by flow cytometry, while apoptosis-related genes using qPCR. The impact of Sin-HSC-imDC and Nar-HSC-imDC on the generation of regulatory T cells (Tregs) was evaluated by mixed lymphocyte reactions. Cytokine expression was quantified using enzyme-linked immunoassays (ELISA). The immunomodulatory effects of Sin-HSC-imDC and Nar-HSC-imDC were evaluated by performing skin transplantation experiments in Balb/c mice recipients models. Kaplan-Meier technique was employed for graft survival outcomes.

RESULTS: In vitro assays, in comparison to Sin-HSC-imDC, Nar-HSC-imDC had higher CD11c expression and lower CD80 as markers for imDCs (P < 0.05) and promoted the generation of Tregs proliferation (P < 0.05). Interleukin 2 (IL-2) and interferon gamma (IFN-γ) levels diminished in Nar-HSC-imDC groups (P < 0.05), but interleukin 10 (IL-10) and transforming growth factor-beta (TGF-β) levels elevated (P < 0.05). And the apoptosis rate of Nar-HSC-DC increased significantly after LPS treatment (P < 0.05). In vivo assays, when Balb/c mice received Nar-HSC-imDC or Sin-HSC-imDC via the tail vein seven days before skin transplantation, mice from the Nar-HSC-imDC group had increased CD4+CD25+CD127- Tregs proliferation in the spleen (P < 0.05), which prolonged skin graft survival, and that was better than in Sin-HSC-imDC group.

CONCLUSION: Nar was exposured more efficient in inducing differentiation of HSC into imDC than Sin. Nar-HSC-imDC had stronger ability in inducing specific immune hypo-responsiveness than Sin-HSC-imDC.