Sirtuin6 Regulates Helminth-induced Intestinal Epithelial Remodeling Through IL-13/STAT6 Signaling Pathway

Background As a common worm species,intestinal-dwelling worms will activate type 2 immunity response and promote intestinal epithelial remodeling after infection.How does the intestinal epithelium perceive the presence of worms and initiate type 2 immunity response? This problem remained unresolved until three independent research papers were published in the two top journals of NATURE and SCIENCE in 2016,which revealed that tuft cells in intestinal epithelium can sense worm infection and initiate type 2 immunity response,so as to promote intestinal epithelial remodeling and worm clearance.At present,there is little understanding about tuft cells,such as which genes regulate the differentiation of tuft cells? What is the specific mechanism of tuft cells sensing worms and its application prospect in forensic medicine.Therefore,the research on tuft cells is also a frontier in the current scientific community.Histone deacetylase sirtuin6（SIRT6）has been proved to be an effective longevity gene in mammals,so it has been studied as a frontier hotspot.SIRT6 plays an important role in regulating metabolism,tumorigenesis,inflammation and aging,and performs different functions in different cell types.At present,the specific function of sirtuin6 in intestinal epithelial cells（IEC）is unclear and needs to be further studied.Objective This project uses the mouse model of specific knockout of Sirt6 or overexpression of signal transduction and transcription activator protein 6（STAT6）in IEC,combined with organic culture and other methods,to explain whether SIRT6 in IEC regulates tuft cell differentiation and intestinal epithelial remodeling induced by worm infection,and to explore whether SIRT6 regulates the expression of Suppressor of cytokine signaling 3（SOCS3）from the perspective of molecular mechanism,Affect the phosphorylation and transcriptional activity of STAT6（Y641）,so as to regulate the remodeling of intestinal epithelium.Methods 1.Preparation of Sirt6 knockout mice in IEC（IEC-KO）and the cell composition of IEC-KO intestinal epithelium was analyzed;To study whether SIRT6 directly regulates the number of tuft and goblet cells by organoid culture.2.Preparation of transgenic mice with specific overexpression of continuously activated STAT6（V547A/T548 A,STAT6vt）in IEC,Tg Vil-STAT6vt;To analyze the composition of small intestinal epithelial cells of Tg Vil-STAT6 vt mice under basic and worm infection;The rescue experiment verified that STAT6,as the downstream of SIRT6,mediates its regulation of intestinal epithelial remodeling at the animal physiological level.3.The molecular mechanism of SIRT6 regulating SOCS3 in IEC and whether SOCS3 in IEC can affect the phosphorylation of STAT6（y641）were studied by cell experiments.Results 1.The loss of SIRT6 in IEC led to the decrease of the number of tuft cells in the intestine,and the decrease of the number of tuft cells and goblet cells in the intestine after H.poly infection.The lack of SIRT6 in the intestinal organoids of mice led to the inhibition of the proliferation of tuft cells and goblet cells induced by IL13;Overexpression of SIRT6 in mouse IEC promoted the proliferation of tuft cells and goblet cells induced by worm infection.2.In the intestinal epithelium,the deletion of SIRT6 resulted in the decrease of STAT6 activity.Transgenic mice with IEC specific overexpression of constitutively active STAT6 vt showed enhanced differentiation of tuft cells and goblet cells;Overexpression of stat6 vt in IEC of IEC-KO mice saves tuft and goblet cell differentiation defects caused by SIRT6 deletion.3.SIRT6 up regulates the phosphorylation of STAT6（Y641）by inhibiting SOCS3 expression.Conclusion 1.The absence of SIRT6 in IEC results in impaired differentiation of tuft cells and goblet cells after worm infection;SIRT6 transgenic mice in IEC showed enhanced epithelial remodeling and more effective worm clearance.2.Overexpression of STAT6 in intestinal epithelium can induce tuft and goblet cell proliferation and promote intestinal epithelial remodeling under worm infection.3.SIRT6 promotes the phosphorylation of STAT6（Y641）by inhibiting the expression of SOCS3,thereby increasing the response to type 2 immune response.