Construction And Functional Study Of A Mouse Model With A Novel Syk Mutation

SYK,a non-receptor tyrosine kinase,is known to have a crucial role in a variety of intracellular signal transduction processes,including innate pathogen recognition,adaptive immune response,bone metabolism and vascular development.Especially,in the immune system,SYK can act as a core signaling molecule to bind and phosphorylate immune receptors to activate downstream signaling pathways.In recent years,more and more attention has been paid to the regulation function of SYK gene in inflammatory diseases,especially its role in the development of allergic reactions and autoimmune diseases,making it a promising target for disease treatment.Our laboratory obtained a rare clinical sample with typical phenotypes of very early-onset inflammatory bowel disease and arthritis.Genome-wide sequencing analysis suggested that a single base gain-of-function mutation occurred in the SYK kinase domain(S550 site),which was most likely the main pathogenic mutation.Therefore,we applied CRISPR/Cas9 technology to construct a mouse model with the corresponding point mutation.The results showed that the mutant mice could spontaneously develop rheumatoid arthritis at the age of five weeks.Moreover,the mutant mice developed phenotypes of the swollen joints,bone erosion caused by the infiltration and erosion of immune cells at the age of 5-week,which were similar to the symptoms of the clinical sample.Nevertheless,we did not detect symptoms of inflammatory bowel disease similar to that of the patient,which also suggested the complexity of the occurrence and development of clinical diseases.It is worth mentioning that until now,only a few animal models of spontaneous rheumatoid arthritis have been developed and among them fewer models were established according to the mutations in clinical patients.So the disease model described in present study is very valuable for disease simulation and mechanism research.In addition,present study conducted a series of preliminary studies on the treatment of this spontaneous inflammation mouse model,including the continuous oral administration of a small molecule inhibitor R406 targeting SYK.What's more,we plan to treat the mice via hematopoietic stem cells gene editing followed by autologous transplantation.In conclusion,we successfully constructed a spontaneous inflammation mouse model of Syk S544 Y point mutation,which can be used as a reliable experimental animal model for pathogenesis research,drug efficacy evaluation and precise gene therapy.