The Mechanism Of EpCAM Deletion Leading To Intestinal Aging And The Improvement Of Intestinal Aging By Ginsenoside Rb1

Background:EpCAM is a transmembrane protein that is highly expressed in intestinal epithelial tissue and is also a surface marker of various stem and progenitor cells.Previous studies have found that:1.EpCAM knockout mice are smaller in size and have a shorter lifespan;2.EpCAM deletion leads to impaired intestinal barrier function;3.EpCAM is highly expressed in intestinal stem cells,etc.However,the role of EpCAM on intestinal stem cells remains to be explored?Aging is a progressive loss of physiological integrity,leading to impairment of body functions and an increased risk of death;its main hallmarks are stem cell exhaustion,telomere attrition,and genomic instability.When the intestine ages,the histological morphology,barrier function and microecology of the intestine will show corresponding age-related changes,which are related to various diseases（such as atherosclerosis,type 2 diabetes,etc.）.Traditional Chinese medicine believes that lack of congenital endowments,emotional disorders,and phlegm,blood stasis,and poisonous pathogens will lead to a comprehensive and gradual decline in the internal organs,qi,blood,essence,and body fluids,which is called aging.How to improve aging is a major socio-economic problem facing all countries today.Studies have confirmed that Fu Fang zhenshu Tiao Zhi（FTZ）can delay intestinal aging,but its main anti-aging active ingredients are still unclear.Ginsenoside Rb1（GRb1）is an important component of many traditional Chinese medicines（such as Pseudo-ginseng,ginseng,etc.）,and is also one of the active components of FTZ.Modern research has proved that GRb1 has various pharmacological effects such as anti-diabetic,anti-aging.But whether GRb1 can improve intestinal aging is still unclear.Objective:1.To explore the molecular mechanism of EpCAM deletion leading to the aging of mouse intestinal epithelial cells.2.To explore the effect and mechanism of ginsenoside Rb1（GRb1）in improving intestinal aging in aged mice from multiple perspectives.Methods:1.EpCAM knockout mice and CACO-2 cells were used as research objects.Pathological analysis was performed by H&E staining,combined with molecular biology techniques such as q PCR,WB and IF etc.,to detect the expression and activity of SIRTs and mTOR in intestinal epithelial cells.2.Rescue experiments with Rapamycin and MDL-800.3.104-week-old（24-month-old）C57BL/6J mouses were selected as a model to explore the effect and mechanism of GRb1 against intestinal aging.H&E and X-gal staining were used for pathological analysis,q PCR,WB,IF and other technologies were used for related gene detection,and mouses feces were collected for 16S r DNA sequencing research.Results:1.Knockout of EpCAM gene reduces the expression of SIRTs family.After administration of MDL-800,the expression of TERT increased andγH2AX was significantly decreased,which significantly improved the presenescence of intestinal epithelial cells in EpCAM^-/-mice.2.Rapamycin inhibits the over-activation of mTORC1 caused by EpCAM deletion,restores telomerase and sirtuins levels,and reduces DNA damage in vitro and in vivo to improve progeria.3.MDL-800 did not inhibit the overactivation of mTORC1.4.GRb1 can reduce the accumulation of senescent cells in the intestinal crypts of aged mice,increase the levels of various claudins to improve the integrity of intestinal epithelium,and upregulate stemness-related genes to improve the function of intestinal stem and progenitor cells.5.GRb1 can improve intestinal aging by regulating the expression of Sirtuins family members in intestinal epithelial cells and regulating the composition and function of intestinal flora in aged mice.Conclusion:Conclusion 1:The study found that the deletion of EpCAM can lead to premature aging of intestinal epithelial cells in EpCAM^-/-mice by reducing the expression of Sirtuins and the activation of the mTORC1 pathway.Conclusion 2:GRb1 can improve intestinal aging by regulating the expression of Sirtuins family members in intestinal epithelial cells of aged mice and regulating the composition and function of gut microbiota in aged mice.