The combination of four main components in Xuebijing injection improved the preventive effects of Cyclosporin A in acute graft-versus-host disease mice by protecting intestinal microenvironment.

Acute graft-versus-host disease (aGVHD) is a major life-threatening complication after Allogeneic Hematopoietic Stem Cell Transplant (allo-HSCT). Although a series of immunosuppressant agents are routinely used as the first-line prevention, the morbidity and mortality rate remains high in allo-HSCT recipients. Our previous work indicated that combining Xuebijing (XBJ) with Cyclosporin A (CSA) is superior to CSA alone in preventing aGVHD. However, it was not clear which compounds in XBJ may prevent aGVHD. Whether the effective compounds in XBJ can be safely combined with CSA to prevent GVHD remain to be evaluated. Here, we accessed whether the combination of four main components in XBJ (C0127) had the same efficacy as XBJ in preventing aGVHD. In addition, the effectiveness of a novel combination therapy (C0127 + CSA) on aGVHD prophylaxis was evaluated using 16 s rRNA sequencing and RNA sequencing approaches in vitro and in vivo. In aGVHD mice, C0127 enhanced the preventive effects of CSA including decreasing mortality, maintaining weight, reducing GVHD score and reducing the expression of IL-6 and TNF-α in serum. Fatal GVHD is a frequent consequence of intestinal tract damage. We found combining C0127 with CSA alleviated the gut damage and maintained the normal physiological function of intestine by H&E staining, intestinal permeability and short chain fatty acid (SCFA) assays. Next, 16 S sequencing analysis of feces showed the combination treatment maintained the intestinal microbial diversity, normalized the intestinal microorganism and prevented flora disorder by reducing the relative abundances of Escherichia coli and Enterococcus. Further, RNA-seq analysis of colonic epithelium revealed C0127 combined with CSA chiefly regulated chemokines and cytokines in IL-17 signaling pathway. The combination treatment reduced the expression of G-CSF and its effector STAT3 (an axis that aggravated gut inflammation and flora disorder) in gut epithelium on mRNA and protein level. These findings indicated that C0127 improved the prevention of CSA in aGVHD mice partially by protecting the gut from damage through normalizing G-CSF signaling, which regulates the intestinal microbiota and the integrity of the epithelial barrier.

Protecting Intestinal Microenvironment Alleviates Acute Graft-Versus-Host Disease.

Acute gut graft-versus-host disease (aGVHD) is a leading threat to the survival of allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Abnormal gut microbiota is correlated with poor prognosis in allo-HSCT recipients. A disrupted intestinal microenvironment exacerbates dysbiosis in GVHD patients. We hypothesized that maintaining the integrity of the intestinal barrier may protect gut microbiota and attenuate aGVHD. This hypothesis was tested in a murine aGVHD model and an in vitro intestinal epithelial culture. Millipore cytokine array was utilized to determine the expression of proinflammatory cytokines in the serum. The 16S rRNA sequencing was used to determine the abundance and diversity of gut microbiota. Combining Xuebijing injection (XBJ) with a reduced dose of cyclosporine A (CsA) is superior to CsA alone in improving the survival of aGVHD mice and delayed aGVHD progression. This regimen also reduced interleukin 6 (IL-6) and IL-12 levels in the peripheral blood. 16S rRNA analysis revealed the combination treatment protected gut microbiota in aGVHD mice by reversing the dysbiosis at the phylum, genus, and species level. It inhibited enterococcal expansion, a hallmark of GVHD progression. It inhibited enterococcal expansion, a hallmark of GVHD progression. Furthermore, Escherichia coli expansion was inhibited by this regimen. Pathology analysis revealed that the combination treatment improved the integrity of the intestinal tissue of aGVHD mice. It also reduced the intestinal permeability in aGVHD mice. Besides, XBJ ameliorated doxorubicin-induced intestinal epithelial death in CCK-8 assay. Overall, combining XBJ with CsA protected the intestinal microenvironment to prevent aGVHD. Our findings suggested that protecting the intestinal microenvironment could be a novel strategy to manage aGVHD. Combining XBJ with CsA may reduce the side effects of current aGVHD prevention regimens and improve the quality of life of allo-HSCT recipients.