Engineered glycocalix regulates stem cell proliferation in murine crypt organoids

At the base of the intestinal crypt, long-lived Lgr5+ stem cells are intercalated by Paneth cells that provide essential niche signals for stem-cell maintenance. This unique epithelial anatomy makes the intestinal crypt one of the most accessible models for the study of adult stem cell biology. The glycosylation patterns of this compartment are poorly characterized and the impact of glycans on stem cell differentiation remains largely unexplored. We found that Paneth cells, but not Lgr5+ stem cells, express abundant terminal N-acetyllactosamine (LacNAc). Employing an enzymatic method to edit glycans in cultured crypt organoids, we assessed the functional role of LacNAc in the intestinal crypt. We show that blocking access to LacNAc on Paneth cells leads to hyperproliferation of the neighbouring Lgr5+ stem cells, which is accompanied by the down-regulation of genes that are known as negative regulators of proliferation Lgr5+ mouse stem cells were sorted from dissociated organoids that had been treated with in situ fucosylation for 4 days or untreated control RNA was isolated and analyzed, quality was determined using a spectrophotometer and was reverse transcribed using a cDNA conversion kit. The cDNA was used on the real-time RT2 Profiler PCR Array (QIAGEN, Cat. no. PAMM-405Z) in combination with RT2 SYBR® Green qPCR Mastermix (Cat. no. 330529). The average fold-change of gene expression in stem cells was analyzed for untreated vs. glycan modified organoids from six biological replicates for 84 genes. CT values were exported to an Excel file to create a table of CT values. This table was then uploaded on to the data analysis web portal at http://www.qiagen.com/geneglobe. Samples were assigned to controls and test groups. CT values were normalized based on a/an Manual Selection of reference genes.