Graft-versus-host disease (GVHD) in the gastrointestinal (GI) tract remains the major cause of morbidity and non-relapse mortality after bone marrow transplantation (BMT). The Paneth cell protein, regenerating islet-derived 3-alpha (REG3α), is a biomarker specific for GI GVHD. REG3α serum levels rose in the systematic circulation as GVHD progressively destroyed Paneth cells and reduced GI epithelial barrier function. Paradoxically, GVHD suppressed intestinal REG3γ (the mouse homologue of human REG3α), and the absence of REG3γ in BMT recipients intensified GVHD but did not change the composition of the microbiome. IL-22 administration restored REG3γ production and prevented apoptosis of both intestinal stem cells (ISCs) and Paneth cells, but this protection was completely abrogated in Reg3g−/− mice. In vitro, addition of REG3α reduced the apoptosis of colonic cell lines. Strategies that increase intestinal REG3α/γ to promote crypt regeneration may offer a novel, non-immunosuppressive approach for GVHD and perhaps for other diseases involving the ISC niche such as inflammatory bowel disease.
Dongchang Zhao, Yeung-Hyen Kim, Seihwan Jeong, Joel K. Greenson, Mohammed S. Chaudhry, Matthias Hoepting, Erik R. Anderson, Marcel R.M. van den Brink, Jonathan U. Peled, Antonio L.C. Gomes, Ann E. Slingerland, Michael J. Donovan, Andrew C. Harris, John E. Levine, Umut Özbek, Lora V. Hooper, Thaddeus S. Stappenbeck, Aaron M. Ver Heul, Ta-Chiang Liu, Pavan Reddy, James L.M. Ferrara