The Study On The Subtypes Of Murine Splenic Red Pulp Macrophages Based On CD169 Expression

Objective:Macrophage heterogeneity has always been a hot topic in immunology.Murine spleen,as a classical immunological research object,has a wide variety of tissue-resident macrophages with different functions.At present,CD 169 expression in partial splenic red pulp macrophages has been mentioned in a number of articles.However,the differences of immunological functions between GD169+ and CD 169-red pulp macrophage subtypes have not been reported.Therefore,we investigated the gene expression profiles of CD169+and CD 169-splenic red pulp macrophages.Methods:First part The spatial distribution of CD169 in red pulp of murine spleen was observed by immunofluorescence.The expression of CD169 in red pulp macrophages of C57BL/6 wild type(WT)and CD 169 knockout(KO)mice were both analyzed by flow cytometry.Sccond part F4/80+red pulp macrophages were enriched and separated into CD169+and CD 169-subtypes,and RNA-sequencing was performed.Differential genes were screened by DESeq2 based on P<0.05&|log2FC|>=1,and functional annotation analysis and functional enrichment analysis were carried out to explore the possible functions of the two groups.Finally,some differential genes were verified by real-time quantitative PCR(qPCR).Results:1、Immunofluorescence of spleen showed that CD 169 was co-localized with red pulp macrophages.Compared with CD 169 knockout(CD 169 KO)mice,flow cytometry confirmed that CD169 was expressed by partial red pulp macrophages of C57BL/6 wild-type(WT)mice.2、RNA sequencing revealed that 485 differentially expressed genes in CD169+and CD 169-subgroups,among which plenty of genes related to inflammation were highly expressed in the CD 169+ population,suggesting that these two groups of macrophages have different functions.Conclusion:1、The CD 169+and CD 169-subtypes have different transcription profiles.2、CD 169+red pulp macrophages are prone to mediate inflammation.