title: Creatine maintains intestinal homeostasis and protects against colitis.
abstract: Creatine, a nitrogenous organic acid, replenishes cytoplasmic ATP at the expense of mitochondrial ATP via the phosphocreatine shuttle. Creatine levels are maintained by diet and endogenous synthesis from arginine and glycine. Glycine amidinotransferase (GATM) catalyzes the rate-limiting step of creatine biosynthesis: the transfer of an amidino group from arginine to glycine to form ornithine and guanidinoacetate. We screened 36,530 third-generation germline mutant mice derived fromN-ethyl-N-nitrosourea-mutagenized grandsires for intestinal homeostasis abnormalities after oral administration of dextran sodium sulfate (DSS). Among 27 colitis susceptibility phenotypes identified and mapped, one was strongly correlated with a missense mutation inGatmin a recessive model of inheritance, and causation was confirmed by CRISPR/Cas9 gene targeting. Supplementation of homozygousGatmmutants with exogenous creatine ameliorated the colitis phenotype. CRISPR/Cas9-targeted (Gatmc/c) mice displayed a normal peripheral immune response and immune cell homeostasis. However, the intestinal epithelium of theGatmc/cmice displayed increased cell death and decreased proliferation during DSS treatment. In addition,Gatmc/ccolonocytes showed increased metabolic stress in response to DSS with higher levels of phospho-AMPK and lower levels of phosphorylation of mammalian target of rapamycin (phospho-mTOR). These findings establish an in vivo requirement for rapid replenishment of cytoplasmic ATP within colonic epithelial cells in the maintenance of the mucosal barrier after injury.
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.|Department of Internal Medicine, Division of Gastroenterology, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Emre
authors.initials: E
authors.lastname: Turer
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: William
authors.initials: W
authors.lastname: McAlpine
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Kuan-Wen
authors.initials: KW
authors.lastname: Wang
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Tianshi
authors.initials: T
authors.lastname: Lu
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Miao
authors.initials: M
authors.lastname: Tang
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Zhan
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.|Quantitative Biomedical Research Center, Department of Clinical Science, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.|Quantitative Biomedical Research Center, Department of Clinical Science, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhan
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Chun-Hui
authors.initials: CH
authors.lastname: Bu
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505.
authors.forename: Anne R
authors.initials: AR
authors.lastname: Murray
authors.affiliation: Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390-8505; bruce.beutler@utsouthwestern.edu.
authors.forename: Bruce
authors.initials: B
authors.lastname: Beutler
mesh_terms: D000579:Amidinotransferases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D064113:CRISPR-Cas Systems; D003092:Colitis / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D003401:Creatine / Q000378:metabolism / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006706:Homeostasis / Q000187:drug effects*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects*; D008297:Male; D008810:Mice, Inbred C57BL; D020125:Mutation, Missense; D020011:Protective Agents / Q000378:metabolism / Q000494:pharmacology
chemical_list: D020011:Protective Agents; D000579:Amidinotransferases; C020681:glycine amidinotransferase; D003401:Creatine
keywords: N-ethyl-N-nitrosourea; glycine amidinotransferase; inflammatory bowel disease; mTOR