FK506 and Lactobacillus acidophilus ameliorate acute graft-versus-host disease by modulating the T helper 17/regulatory T-cell balance.

BACKGROUND: Graft-versus-host disease (GvHD) is a critical complication after allogeneic hematopoietic stem cell transplantation (HSCT). The immunosuppressants given to patients undergoing allogeneic HSCT disturb the microbiome and the host immune system, potentially leading to dysbiosis and inflammation, and may affect immune function and bone marrow transplantation. The intestinal microbiome is a target for the development of novel therapies for GvHD. Lactobacillus species are widely used supplements to induce production of antimicrobial and anti-inflammatory factors. METHODS: We determined the effect of the combination of Lactobacillus acidophilus and FK506 on GvHD following major histocompatibility complex-mismatched bone marrow transplantation. RESULTS: The combination treatment suppressed IFN-γ and IL-17-producing T cell differentiation, but increased Foxp3+Treg differentiation and IL-10 production. Also, the combination treatment and combination treated-induced Treg cells modulated the proliferation of murine alloreactive T cells in vitro. Additionally, the combination treatment upregulated Treg-related genes-Nt5e, Foxp3, Ikzf2, Nrp1 and Itgb8-in murine CD4+-T cells. The combination treatment also alleviated GvHD clinically and histopathologically by controlling the effector T cell and Treg balance in vivo. Moreover, the combination treatment decreased Th17 differentiation significantly and significantly upregulated Foxp3 and IL-10 expression in peripheral blood mononuclear cells from healthy controls and liver transplantation (LT) patients. CONCLUSIONS: Therefore, the combination of L. acidophilus and FK506 is effective and safe for patients undergoing allogeneic hematopoietic stem cell transplantation.

Combination Treatment With Metformin and Tacrolimus Improves Systemic Immune Cellular Homeostasis by Modulating Treg and Th17 Imbalance.

We examined the effect of combination therapy with metformin and tacrolimus on immune parameters including T regulatory (Treg) and type 17 helper T (Th17) cells in vitro and in vivo in mice and in liver transplantation (LT) patients. T cell proliferation and subtypes after in vitro T cell activation or allogeneic stimulation were evaluated. RNA sequencing and microarray analysis were used to evaluate differences in gene expression. Metformin and tacrolimus were administered to mice with graft-versus-host disease (GVHD) and the effects in vivo were assessed. Five LT patients were treated with metformin and the changes in Treg and Th17 cells examined. Combination therapy decreased Type 1 helper T (Th1) and Th17 cells present after in vitro T cell activation, whereas genes associated with Treg were overexpressed. During in vitro allogeneic stimulation, combination therapy increased Treg cells and decreased T cell proliferation and pro-inflammatory markers. In mice with GVHD, combination treatment decreased the clinical and pathological severity of GVHD. In LT patients, addition of metformin increased the peripheral percentage of CD4+Treg and CD8+Treg cells and decreased CD4+Th17. Our study suggests that the addition of metformin to tacrolimus may improve immunological balance by increasing Treg cells and decreasing Th17 cells.

Cucurbitacin E ameliorates acute graft-versus-host disease by modulating Th17 cell subsets and inhibiting STAT3 activation.

Cucurbitacin E (CuE) is a biochemical compound found in plants that are members of the family CuE has been studied for its roles in anti-inflammation and the inhibition of angiogenesis as well as for its properties as an antioxidant. CuE is a new agent that was identified as a selective inhibitor of the signal transducer and activator of transcription 3 (STAT3)-related pathway. STAT3, a pivotal transcription factor for Th17 differentiation, is critical for T cell alloactivation in acute graft-versus-host disease (aGvHD). We investigated whether CuE attenuates the development of aGvHD through the suppression of Th17 cells. The alloreactive proliferation of mouse and human T cells was reduced by CuE treatment. CuE also decreased pro-inflammatory cytokines, such as IL-17 and IFN-γ, in alloreactive T cells. STAT3-responsive and IL-17A-promoter activities were also suppressed by CuE treatment, confirming that activated STAT3 was decreased by CuE treatment. To construct an aGvHD-induced mouse line, splenocytes and bone marrow cells from C57BL/6 mice were transplanted into BALB/c mice with complete mis-matched major histocompatibility complex molecules. CuE was administered to aGvHD animals 3 days per week via intraperitoneal injection. CuE attenuated the severity of aGvHD disease-related scores compared to the vehicle group. CuE inhibited skin inflammation and fibrosis, as evidenced by the expression of α-Sma and Col-I in aGvHD mice compared to the vehicle group. Additionally, aGvHD mice treated with CuE showed improved histopathological features in the small and large intestines, whereas the vehicle group showed collapsed villi in the small intestine and cryptic structures in the large intestine. We also observed a marked reduction of pro-inflammatory cytokines in the intestinal tissue. Collectively, our data suggest that CuE could serve as a therapeutic agent for patients with aGvHD.