| BackgroundLECT2 was first identified as a leukocyte-derived chemokine with the ability to chemotactic neutrophils,and more and more evidence shows that LECT2 is a multifunctional cytokine.According to related reports,in humans and mice,LECT2 is mainly produced in the liver and secreted into the blood to participate in various physiological functions.LECT2 gene defects or abnormal expression are associated with various pathological conditions,such as diabetes,systemic amyloidosis,atherosclerosis,liver cirrhosis and liver cancer.These studies have fully demonstrated that LECT2 is involved in multiple functions in different tissues and organs.However,in mammals,it is currently unclear which cells express LECT2.In addition,as a chemokine,the function of LECT2 in inflammatory immunity remains to be studied.Although it has been reported that the administration of recombinant LECT2 improved the protective immunity of sepsis mice,there is still a lack of in vivo experiments to confirm the role and mechanism of LECT2 in inflammation and immunity.Zebrafish are vertebrates,and they are genetically and physiologically similar to mammals including humans.And its embryo is transparent and fertilized in vitro,which is suitable for in vivo imaging and longitudinal analysis.These characteristics give zebrafish a unique advantage in studying inflammation and immunity.In addition,zebrafish have a fully functional innate immune system and their functions and mechanisms are conserved.As a model of inflammatory and immune diseases,zebrafish has important reference significance for explaining its molecular mechanism.In zebrafish,LECT2 has three homologous genes,among which lect2l has the highest sequence similarity,but there is no report about the expression and function of lect2l in zebrafish.This study intends to study zebrafish lect2l through sequence,expression and function and confirm its evolutionary conservatism.And on this basis,we will further explore the role and mechanism of lect2l in inflammatory immunity.Objective:1)Confirm the evolutionary conservation of zebrafish lect2l gene;2)To study the role and mechanism of lect2l in inflammation and immunity.Method:1)Identify the expression pattern of lect2l in zebrafish by in situ hybridization,laser confocal microscope photo observation,flow cytometry and other methods;2)Use CRISPR-CAS9 and other technologies to construct lect2l mutant zebrafish;3)Construct fluorescent-labeled transgenic zebrafish and lect2l overexpressed transgenic zebrafish by vector construction and microinjection;4)Observe role of lect2l in inflammatory immunity through Tg(lect2l:GFP),lect2l mutant zebrafish.Results:1)lect2l is highly conserved with humans and mice in sequence.In addition,lect2l is expressed in the liver of zebrafish,and its mutation weakens the resistance of juvenile zebrafish to E.coli,which shows that lect2l is also highly conserved in expression and function.2)Under physiological conditions,lect2l is specifically expressed in liver and neutrophils;however,when injured or infected,lect2l can be directly expressed in injured or infected tissues.3)The lack of lect2l does not affect the number of zebrafish immune cells under physiological conditions.However,during infection,lect2l mutations will lead to a reduction in the number of macrophages involved in the immune response.Conclusion:1)lect2l is highly conservative with mammals such as humans or mice in evolution;2)lect2l is specifically expressed by the liver and macrophages under physiological conditions,but it can be directly secreted from local tissue cells other than the liver and neutrophils under emergency conditions such as infection;3)lect2l may mediate the inflammation and immunity of zebrafish through macrophages. |
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