| Intestinal homeostasis is a dynamic equilibrium state formed by the interaction of intestinal mucosal barrier and intestinal environment.Intestinal mucosa includes a mechanical barrier,which is also called intestinal mucosal epithelial structure,including the connection between intestinal epithelial cells and intestinal epithelial cells,with the function of absorbing nutrients and excluding harmful substances from the barrier.When the intestinal mucosa is damaged,the intestinal epithelial cells near the wound will lose their polarity,and the microvilli on the cell surface will disappear,so that the barrier function is impaired and endotoxins and bacteria are easy to enter.In order to repair the intestinal mucosa,the surrounding intestinal epithelial cells will migrate rapidly,and the stem cells in the basement of the crypts will proliferate and differentiate to repair the intestinal mucosa.Cerebral cavernous hemangioma(CCM)is a kind of expansion of capillaries as the main characteristics of the central nervous system diseases,CCM disease related proteins(KRIT1,CCM2 PDCD10)has been proven in endothelial cells and its outer membrane connection and barrier function has a certain influence,the lack of three proteins can destroy the endothelial cells of two functions: the extracellular matrix and the formation of blood vessels here.However,its role in epithelial barrier function is still unclear.Therefore,we intend to explore the role and mechanism of CCM in intestinal epithelial homeostasis through CCM knockout mice.Methods: CCM knockout mice and wild-type mice were intramuscular injected with tamoxifen(TAM)to control the specific expression of CCM protein for two weeks.The distribution of cadherin in epithelial tissues was detected by immunofluorescence assay,and the morphology of intestinal epithelial villi cells was observed by staining with HE and PAS.The expression and distribution of lysozyme in intestinal epithelial tissues were detected by immunohistochemistry.Results:1.Compared with wild-type mice,CCM knockout mice began to show more significant weight loss at day 5;In addition,the colon shortening was more obvious after TAM induction in CCM gene knockout mice,and the intestinal tissue pathological features were more obvious,and the intestinal permeability was changed.2.Compared with wild type mice,TAM PDCD10 intestinal epithelium specificity knockout mice intestinal tissue after induction E-Cadherin(calcium epithelial mucin)expression decreased,compared with the control group,experimental group of E-Cadherin protein from uniform distribution into polarity distribution,gathered at the side of the base,intestinal epithelial cell polarity changes,HE staining and PAS stainingvisible intestinal villi cell fusion phenomenon;3.Alcian blue of PDCD10 epithelium-specific knockout mice showed decreased intestinal epithelial goblet cells,decreased Lysozyme in crypts,increased villi,and no expression in the control group,indicating a change in the position of pann cells.Increased expression of ezrin and pNHE3 suggested that specific knockout of PDCD10 affected upward migration of intestinal epithelial cells.These results suggest that CCM can regulate intestinal epithelial cell migration and differentiation.4.In Ki67 staining,total crypt cells increased,Ki67 positive cells slightly decreased,and negative cells increased.Two hours after brdu injection,brdu positive cells in each crypt slightly decreased,and Olfm4(olfenin-like protein)expression increased.Cleaved caspase-3(Cleaved caspase-3)was expressed only in villi,and the expression of positive cells increased compared to the control group,suggesting that intestinal epithelial apoptosis was affected by CCM loss.Conclusions: these data suggest that CCM may modulate enteroepithelial homeostasis through a number of different pathways: cell polarization,cell migration and differentiation,and proliferation and apoptosis of enteroepithelial cells. |
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