Standard: Human intestinal organoids.

Organoids have attracted great interest for disease modelling, drug discovery and development, and tissue growth and homeostasis investigations. However, lack of standards for quality control has become a prominent obstacle to limit their translation into clinic and other applications. "Human intestinal organoids" is the first guideline on human intestinal organoids in China, jointly drafted and agreed by the experts from the Chinese Society for Cell Biology and its branch society: the Chinese Society for Stem Cell Research. This standard specifies terms and definitions, technical requirements, test methods, inspection rules for human intestinal organoids, which is applicable to quality control during the process of manufacturing and testing of human intestinal organoids. It was originally released by the Chinese Society for Cell Biology on 24 September 2022. We hope that the publication of this standard will guide institutional establishment, acceptance and execution of proper practical protocols and accelerate the international standardization of human intestinal organoids for applications.

Mesenchymal-epithelial interaction regulates gastrointestinal tract development in mouse embryos.

After gut tube patterning in early embryos, the cellular and molecular changes of developing stomach and intestine remain largely unknown. Here, combining single-cell RNA sequencing and spatial RNA sequencing, we construct a spatiotemporal transcriptomic landscape of the mouse stomach and intestine during embryonic days E9.5-E15.5. Several subpopulations are identified, including Lox+ stomach mesenchyme, Aldh1a3+ small-intestinal mesenchyme, and Adamdec1+ large-intestinal mesenchyme. The regionalization and heterogeneity of both the epithelium and the mesenchyme can be traced back to E9.5. The spatiotemporal distributions of cell clusters and the mesenchymal-epithelial interaction analysis indicate that a coordinated development of the epithelium and mesenchyme contribute to the stomach regionalization, intestine segmentation, and villus formation. Using the gut tube-derived organoids, we find that the cell fate of the foregut and hindgut can be switched by the regional niche factors, including fibroblast growth factors (FGFs) and retinoic acid (RA). This work lays a foundation for further dissection of the mechanisms governing this process.

BMP gradient along the intestinal villus axis controls zonated enterocyte and goblet cell states.

Intestinal epithelial cells derive from stem cells at the crypt base and travel along the crypt-villus axis to die at the villus tip. The two dominant villus epithelial cell types, absorptive enterocytes and mucous-secreting goblet cells, are mature when they exit crypts. Murine enterocytes switch functional cell states during migration along the villus. Here, we ask whether this zonation is driven by the bone morphogenetic protein (BMP) gradient, which increases toward the villus. Using human intestinal organoids, we show that BMP signaling controls the expression of zonated genes in enterocytes. We find that goblet cells display similar zonation involving antimicrobial genes. Using an inducible Bmpr1a knockout mouse model, we confirm that BMP controls these zonated genes in vivo. Our findings imply that local manipulation of BMP signal strength may be used to reset the enterocyte "rheostat" of carbohydrate versus lipid uptake and to control the antimicrobial response through goblet cells.

DDB1 promotes the proliferation and hypertrophy of chondrocytes during mouse skeleton development.

The proliferation and hypertrophy of chondrocytes play important roles in endochondral ossification, which is tightly regulated during skeleton development. However, the regulation mechanism remains largely unknown. Here we show that DDB1 (Damaged DNA Binding Protein 1) has a critical function in the development of growth plates. Using chondrocyte-specific DDB1 knockout mice, we found that DDB1 deletion in chondrocytes results in dwarfism due to the aberrant skeleton development. The structure of growth plate in tibia becomes disordered at P21, not in femur. But at P70, the changes are severer in femur than tibia. Chondrocyte proliferation and differentiation are attenuated and asynchronous in both tibia and femur at P7 and P21. Furthermore, DDB1 deficiency induces p27 upregulation and subsequent cell cycle arrest in primary chondrocytes. Therefore, our data reveal that DDB1 is essential for the skeleton development by controlling chondrocyte proliferation and differentiation.

A PROTAC peptide induces durable ß-catenin degradation and suppresses Wnt-dependent intestinal cancer.

Aberrant activation of Wnt/ß-catenin signaling has been associated with the onset and progression of many types of tumors and thus ß-catenin represents one attractive intracellular target for cancer therapy. Based on the Axin-derived peptide that binds to ß-catenin, two stapled peptides SAHPA1 and xStAx were reported to enhance or impair Wnt/ß-catenin signaling, respectively. In this study, we designed PROTACs (proteolysis targeting chimeras) by coupling SAHPA1 or xStAx with the VHL ligand to achieve efficient ß-catenin degradation. The obtained xStAx-VHLL sustained ß-catenin degradation and manifested strong inhibition of Wnt signaling in cancer cells and in APC-/- organoids. Furthermore, xStAx-VHLL could effectively restrain tumor formation in BALB/C nude mice, and diminish the existing tumors in APCmin/+ mice. More importantly, xStAx-VHLL could potently inhibit the survival of colorectal cancer patient-derived organoids. These findings suggest that xStAx-VHLL exhibits the ability of cancer prevention and cure, highlighting the potential of ß-catenin degrader PROTACs as a new class of promising anticancer agent.

[Purification, identification and characterization of an endoglucanase Egn20 from Fusarium sp. Q7-31T].

OBJECTIVE: The endoglucanase from Fusarium sp. Q7-31T was isolated, purified, identified and characterized to provide data for enzyme system of Fusarium sp. . [Methods] Strain was cultured in liquid fermentation with oat straw as carbon source, the endoglucanase was purified by using Sephacry S-100 chromatography and DEAE-sepharose ion-exchange column chromatography and the enzymatic properties were studied. The protein was identified using MADIL-TOF-TOF. RESULTS: An endoglucanase was purified and named Egn20. The molecular weight was 55.37 kDa and isoelectric point (pI) was 7.44. Egn20 had optimal activity with carboxymethyl cellulose at 40 degrees C and pH 6.0, stabilized at 45 degrees C and pH 5.0 - 7.0, activated by Fe2+, inhibited by Na+, Ca2+, Mg2+, Zn2+, K+ and inactivated by Hg2+. The enzymatic properties and MADIL-TOF-TOF results suggested that Egn20 belongs to GH7 family. CONCLUSION: Our results may provide important data for the study of Fusarium sp. enzyme system.