P005 Exosome miR-132-3p derived from Adipose Stem Cells in Creeping fat Regulates RASA1/ERK1/2-dependant Lymphatic Functions and Improve Colitis and Mesenteritis

Abstract

Abstract Background Creeping fat (CrF) is an important pathological characteristics of Crohn’s disease (CD) and characterized by lymphangiogenesis and abnormal lymphatic functions. Adipose tissue derived stem cells (ADSCs) can regulate surrounding cells function by delivering exosomes (exo). However, whether CrF-ADSC-exo could affect lymphatic endothelium to regulate lymphatic functions, and further influence procession of mesenteritis and colitis remains elusive. Methods Paired CrF and uninvolved mesenteric adipose tissue (uMAT) samples were collected from CD patients during operation, and exosomes were separated by ultra-centrifugation. Human lymphatic endothelial cells (HLECs) were cultured in vitro and evaluated the abilities in proliferation, migration and tube formation. IL-10 KO mice was used for assessing the treatment of CrF-ADSC-exo in experimental colitis and mesenteritis. Results ADSC-derived exosomes from paired CrF and uMAT samples were confirmed to transfer to LEC by immunofluorescence microscope. In vitro, CrF-ADSC-exo effectively stimulated HLECs in proliferation, migration and tube formation. In vivo, CrF-ADSC-exo injection increased lymphangiogenesis in MAT and improved lymphatic drainage, and further alleviated colitis and mesenteritis in IL-10 KO mice. We next adopted high-throughput sequencing of paired CrF-ADSC-exo and uMAT-ADSC-exo, and validated significantly high expression of miR-132-3p in CrF-ADSC-exo. In vitro, upregulation or downregulation of miR-132-3p in HLECs stimulated or inhibited the lymphatic abilities in proliferation, migration and tube formation, respectively. Mechanically, we demonstrated that CrF-ADSC-exo regulated lymphatic function through miR-132-3p-RASA1-ERK1/2 axis by western blot. CrF-ADSC-exo miR-132-3p improved lymphatic drainage function in MAT and reduced inflammatory colon and mesentery in IL-10 KO mice. The higher level of miR-132-3p in CrF from CD patients was tightly correlated with inflammatory mediators expressions when compared with uMAT and healthy MAT. Conclusion Our study discovers that CrF-ADSC-exo improves lymphatic functions and alleviates colitis and mesenteritis through miR-132-3p/RASA1/ERK1/2 axis, which discloses new role of CrF involved in CD procession and provides novel insight for CD treatment.