技术资料

The intestinal epithelial regeneration is driven by intestinal stem cells under homeostatic conditions. Differentiated intestinal epithelial cells,such as Paneth cells,are capable of acquiring multipotency and contributing to regeneration upon the loss of intestinal stem cells. Paneth cells also support intestinal stem cell survival and regeneration. We report here that depletion of an RNA-binding protein named polypyrimidine tract binding protein 1 (PTBP1) in mouse intestinal epithelial cells causes intestinal stem cell death and epithelial regeneration failure. Mechanistically,we show that PTBP1 inhibits neuronal-like splicing programs in intestinal crypt cells,which is critical for maintaining intestinal stem cell stemness. This function is achieved at least in part through promoting the non-productive splicing of its paralog PTBP2. Moreover,PTBP1 inhibits the expression of an AKT inhibitor PHLDA3 in Paneth cells and permits AKT activation,which presumably maintains Paneth cell plasticity and function in supporting intestinal stem cell niche. We show that PTBP1 directly binds to a CU-rich region in the 3' UTR of Phlda3,which we demonstrate to be critical for downregulating the mRNA and protein levels of Phlda3. Our results thus reveal the multifaceted in vivo regulation of intestinal epithelial regeneration by PTBP1 at the post-transcriptional level. View Publication

While readily achieved in cell lines,the application of CRISPR-Cas9 gene editing in human-derived organoids suffers from limited efficacy and complex protocols. Here,we describe a multi-guide RNA CRISPR-Cas9 gene-editing protocol which efficiently achieves complete gene knockout in adult human colonic organoids. This protocol also describes crucial steps including how to harvest patient tissue to maximize gene-editing efficacy and a technique to validate gene knockout following editing with immunofluorescent staining of the organoids against the target protein. View Publication

In cancer microenvironment,aberrant glycosylation events of ECM proteins and cell surface receptors occur. We developed a protocol to generate 3D bioprinted models of colorectal cancer (CRC) crosslinking hyaluronic acid and gelatin functionalized with three signalling glycans characterized in CRC,3'-Sialylgalactose,6'-Sialylgalactose and 2'-Fucosylgalactose. The crosslinking,performed exploiting azide functionalized gelatin and hyaluronic acid and 4arm-PEG-dibenzocyclooctyne,resulted in biocompatible hydrogels that were 3D bioprinted with commercial CRC cells HT-29 and patient derived CRC tumoroids. The glycosylated hydrogels showed good 3D printability,biocompatibility and stability over the time. SEM and synchrotron radiation SAXS/WAXS analysis revealed the influence of glycosylation in the construct morphology,whereas MALDI-MS imaging showed that protein profiles of tumoroid cells vary with glycosylation,indicating that sialylation and fucosylation of ECM proteins induce diverse alterations to the proteome of the tumoroid and surrounding cells. View Publication

Human intestinal organoids (HIOs) derived from pluripotent stem cells provide a valuable model for investigating human intestinal organogenesis and physiology,but they lack the immune components required to fully recapitulate the complexity of human intestinal biology and diseases. To address this issue and to begin to decipher human intestinal-immune crosstalk during development,we generated HIOs containing immune cells by transplanting HIOs under the kidney capsule of mice with a humanized immune system. We found that human immune cells temporally migrate to the mucosa and form cellular aggregates that resemble human intestinal lymphoid follicles. Moreover,after microbial exposure,epithelial microfold cells are increased in number,leading to immune cell activation determined by the secretion of IgA antibodies in the HIO lumen. This in vivo HIO system with human immune cells provides a framework for future studies on infection- or allergen-driven intestinal diseases. View Publication