Effect Of LAPTM5 Overexpression On The Proliferation And Activation Of Mouse B Lymphocyte Induced By LPS

Objective: Systemic lupus erythematosus(systemic lupus erythematosus,SLE)is a typical systemic autoimmune disease.The appearance of immune cell phenotype,dysfunction of function and elimination of autoapoptotic cells in patients with lupus erythematosus lead to the production of a large number of autoantibodies in the body.Immune complex deposition and multiple organ damage mainly in kidney.Systemic lupus erythematosus is associated with excessive activation of B cells in vivo to produce a large number of antibodies.In lupus patients and lupus mice,lesions are the most common autoimmune disease with genetic defects in B cells,mainly due to excessive B cells.LAPTM5(lysosomal-associated protein transmembrane 5)is a lysosomal associated protein found in hematopoietic tissues such as bone marrow,thymus and spleen,which is involved in the degradation of lysosome pathway of phagocytic substance.Mainly expressed in hematopoietic tissue,it is the transporter of phagocytosis and swallowing substance,which is involved in the recruitment of ubiquitin to transport it to lysosomes for degradation.The biological function of LAPTM5 in immune cells is still unclear.It was found that it was involved in the negative regulation of the surface receptors of Tn B lymphocytes,the positive regulation of macrophages’ pro-inflammatory signals,and the antigen-presenting effect of dendritic cells on lipid antigens.Its abnormal expression or activity may not only cause changes in the immunological activity of B cells,but also may cause macrophages to eliminate apoptotic cells,activating the autoimmune response and producing inflammatory factors by uncleared nucleic acids in the cells.This leads to lupus lesions.The results of real-time quantitative PCR showed that the LAPTM5 m RNA expression of NZB mice was significantly lower than that of NZW mice,and LAPTM5 m RNA sequencing of NZB mice showed that the expression of LAPTM5 m RNA in NZB mice was significantly lower than that in NZW mice,and the results of LAPTM5 m RNA sequencing in NZB mice showed that the expression of LAPTM5 m RNA in NZB mice was significantly lower than that in NZW mice.A sense mutation occurred at the 656th base of the gene(amino acid sequence at the C-terminal of A→G),causing protein changed from lysine to arginine(Lys→Arg),which resulted in a change in the biological activity of the gene.Therefore,the influence of cell immunological activity remains to be studied.By constructing LAPTM5 wild-type and NZB adenovirus,we studied the effect of LAPTM5 overexpression on WEHI231 proliferation and activation induced by LPS by infecting mouse B lymphocyte WEHI231 in vitro.Methods: q RT-PCR was used to detect the expression of LAPTM5 in RAW264.7,WEHI231,and NIH3T3 cells;The LAPTM5 WT and NZB adenovirus was used to infect WEHI231 cells in vitro;WEHI231 cells cultured in vitro were stimulated by LPS(1μg/ml).q RT-PCR was used to detect the expression of LAPTM5,IL-6 and TNFαm RNA in WEHI231 cells,CCK8 assay was performed to evaluate the proliferation of WEHI231 cells.Results: LAPTM5 was highly expressed in RAW264.7,but lower expressed in WEHI231,not expressed in NIH3T3 cells.The expression level of LAPTM5 m RNA infected with LAPTM5 WT and NZB adenovirus was significantly increased(P<0.05).The proliferation in WEHI231 cells of LAPTM5 overexpression stimulated by LPS was obviously increased(P < 0.05).The expression levels of IL-6 and TNFαm RNA in WEHI231 cells of LAPTM5 overexpression stimulated by LPS were obviously increased(P < 0.05).The LAPTM5 NZB adenovirus had no effect on cell proliferation and activation(P>0.05).Conclusion: LAPTM5 overexpression can promote the proliferation and activation of WEHI231 induced by LPS.