The Mechanism And Effect Of MarvelD1 On Mouse Small Intestinal Epithelium Development

This study was based on the MarvelD1 whole-body knockout mouse model(MarvelD1^-/-)which was established by the Cre-LoxP system combined with mating protocol.In this study,we explored the effects of MarvelD1 gene on intestinal development and its regulatory molecules and then constructed a signal network that MarvelD1 regulates intestinal epithelial development and functional cell differentiation in mice.The results of in hybridization demonstrated that MarvelD1 was highly expressed in mouse endoderm at two time points of embryonic E12.5 and E15.5 days,indicating MarvelD1 play an important role in mouse digestive tract development and small intestine maturation.When sampling the small intestine from the mouse on the day of birth,it was found that the MarvelD1 knockout type(MarvelD1^-/-)mice showed a defective phenotype with a shortened intestinal length compared to the MarvelD1 gene wild type(MarvelD1^+/+)mice.Weighing the body weight of wild-type and MarvelD1 knockout mice at various time points after birth,it was found that there was a significant difference in the body weight of MarvelD1 knockout mice in early pregnancy compared with the body weight of MarvelD1 wild type mice.In this study,the mice small intestine samples were selected for histomorphometry and molecular level analyses at different developmental time points on the day of birth and 1 week,2 weeks and 6-8 weeks postnatal.The MarvelD1 heterozygous(MarvelD1^+/-)male and the MarvelD1 heterozygous(MarvelD1^+/-)females mice were interbred.The offspring were collected after the genotype verification,paraffin-embedded and Liquid nitrogen small intestine tissues were freezed for subsequent experimental analysis.The results of HE staining and immunohistochemistry showed that at the early stage after birth,MarvelD1^-/-mice had obvious structural defects in the intestinal epithelium and the epithelial cells were disorderly and disorderly as compared with MarvelD1^+/+mice.Membranal separation,functional cell number reduction,abnormal distribution and changes in cell morphology were observed.Considering that the small intestine as a characteristic organ of endoderm has a lifelong continuous renewal and based on important biological processes at different development time points.In order to further explore the molecular mechanism of the phenotype of small intestinal tissue defects,the prenatal embryos was collected as well.The expression of key regulatory molecules in the Wnt and Hippo signaling pathways in the intestine of mice at various time points was analyzed by Real-time PCR using the digestive tract of mouse and the RNA of mouse small intestine at various time points after birth.The results showed that the expression levels of regulatory molecules in Wnt signaling pathways such as Wnt5a,Dkk2,Lrp6,APC,Axin and LATS1,SAV1,Tead2/4,Smad4 in the Hippo signaling pathway were significantly decreased in the small intestine of MarvelD1^+/+mice.The expression levels of these regulatory molecules showed a significant down-regulation with the progression of development;whereas there was no change with the expression levels of regulatory molecules in the above-mentioned signaling pathways in the small intestine of MarvelD1^-/-mice at the same age.This result suggests that MarvelD1 exerts its biological effects on the development and function of the small intestine by affecting the expression of key regulatory molecules in the Wnt signaling pathway and the Hippo signaling pathway.In summary,the results of this study indicated the aberrant alternations in the intestinal epithelial tissue phenotype in MarvelD1 knockout mice.MARVELD1 mainly affects molecules in Wnt signaling pathway during postnatal intestinal epithelial development in mice.The expression of some regulatory molecules in the Hippo signaling pathway regulate the development of the intestinal epithelium and may affect the function of the small intestine.The molecular analysis of MARVELD1 regulation of intestinal epithelial development and functional cell differentiation in mice was established by integrating the results of prenatal detection.It provides a new idea for understanding the role of MarvelD1 in the development of mouse endoderm organs.