The human intestine secretes a substance called an antibacterial peptide (a substance having antibacterial activity in which 30 or more amino acids are linked) from its surface to suppress the growth of pathogens in the intestine and keep the intestinal flora healthy.In particular, α-defensin, an antibacterial peptide secreted by panelo cells that protect the small intestine from pathogens, has a high bactericidal action against pathogens, but hardly kills symbiotic bacteria that are beneficial to humans.

　This time, administration of R-Spondin1 to healthy mice promoted the differentiation of paneto cells from intestinal tissue stem cells, increased the number of panel cells, and increased the α-defensin concentration.At this time, it was confirmed that the intestinal flora did not change significantly, and that -α-defensin hardly killed the symbiotic bacteria.

　In addition, after bone marrow transplantation in mice, panelo cells decreased and α-defensin was depleted, but administration of R-Spondin1 at the time of transplantation alleviated these changes.In addition, abnormalities in the gut microbiota that occurred after transplantation were clearly improved, adverse immune responses after transplantation (graft-versus-host disease) were improved, and survival time after transplantation was prolonged.In addition, when α-defensin, an antibacterial peptide, was purified and orally administered to mice after transplantation, abnormalities in the intestinal flora and adverse immune responses after transplantation were improved.

　The treatment method developed this time is a completely new physiological treatment method that is said to have few side effects, and is expected to be applied to various diseases such as diabetes, collagen disease, allergies, and cancer in addition to hematopoietic stem cell transplantation.

Paper information:[Journal of Experimental Medicine] R-Spondin 1 expands Paneth cells and prevents dysbiosis induced by graft-versus-host disease