Expession And Clinical Significance Of LC3-associated Phagocytosis Related Genes In Systemic Lupus Erythematosus

Objective:To detemine the expression of T cells immunoglobulin and mucin domain containing molecule 4(TIM4),Beclin1,ATG5,Microtubule-associated protein 1 light chain 3(LC3),Tectonin beta-propeller repeat-containing protein 1(Tecpr1)in the different stages of LC3-associated phagocytosis(LAP)and WD repeat domain,phosphoinositide interacting2(WIPI2)which is required for canonical autophagy but dispensible for LAP in the peripheral blood mononuclear cell(PBMCs)of Systemic Lupus Erythematosus(SLE),and assess their relationship with disease activity and clinical manifestation,to discuss the role of LC3-associated phagocytosis in the pathogenesis of Systemic Lupus Erythematosus.Methods:1.90 SLE patients were recruited in the study as experimental group,58healthy volunteers were recruited as healthy controls,and Demographic characteristics,clinical characteristics and laboratory data were collected.Blood samples of all subjects were collected in the morning.2.The expression mRNA level of TIM4,Beclin1,ATG5,LC3,WIPI2,Tecpr1 was detected by real time quantitative PCR(RT-qPCR)in SLE subjects and age and sex matched healthy controls.Comparing the mRNA level of TIM4,Beclin1,ATG5,LC3,WIPI2 and Tecpr1 of the peripheral blood mononuclear cell(PBMCs)in SLE and healthy controls,and accessing their correlations with disease activity and clinical manifestation.3.The statistical software SPSS 19.0 and GraphPad Prism7.0 were used to perform statistical analyses and drawing pictures respectively.The mean and standard deviation(SD)or the median(Quartile Range)(M(Q_R))were used to summarize variables.Percentage(%)was used to summarize qualitative data.Comparisons of continuous variables between two groups were done by the Independent sample t-test in the case of normal variables and the Mann-Whitney U-test in the case of non-normal variables.Chisquare test was used to compare the qualitative data.Rank sum test was used to compare two samples of rank data.For correlations between the mRNA expression of TIM4,Beclin1,ATG5,LC3,Tecpr1 and SLEDAI,Spearman~'s correlation was used for non-normal variables.P<0.05 was considered as statistically significant.Results:1.The level of TIM4 mRNA level of SLE patients(n=90)was 0.62(1.23)lower than that in controls(n=46)1.23(1.48),P<0.01.The level of Beclin1mRNA level of SLE patients(n=90)was 0.71(1.22)lower than that in controls(n=58)0.93(0.82),P<0.05.The level of ATG5 mRNA of SLE patients(n=90)was 0.92(1.24)lower than that in controls(n=58)1.44(1.65),P<0.05.The level of LC3 mRNA of SLE patients(n=90)was 0.62(0.73)lower than that in controls(n=58)1.06(2.25),P<0.01.The level of Tecpr1 mRNA of SLE patients(n=90)was 0.43(0.57)lower than that in controls(n=58)1.14(0.83),P<0.01.However,The levels of WIPI2 mRNA in SLE patients was not significantly different from that in controls.(Note:The two groups of variables were tested as non-normal variables,the Mann-Whitney U-test was used,and the median(Quartile Range)(M(Q_R))were used to summarize variables.)2.Correlations between TIM4 mRNA in PBMCs and SLEDAI as well as clinical manifestation:There were negatively correlations between TIM4level and SLEDAI(r=-0.244,P<0.05).The rates of SLE patients with proteinuria rate in the level of TIM4 mRNA<1.23 were higher than that in TIM4 mRNA?1.23,P<0.05.The SLEDAI scores of SLE patients with the level of TIM4 mRNA<1.23 was higher than SLE patients with the level of TIM4 mRNA?1.23,P<0.05.3.Correlations between Beclin1 mRNA in PBMCs and SLEDAI as well as clinical manifestation:There were negatively correlations between Beclin1level and SLEDAI(r=-0.225,P<0.05).The rates of SLE patients with arthritis,blood system damage and Anti HIS antibody positive rate in the level of Beclin1 mRNA<0.93 were higher than that in Beclin1 mRNA?0.93,P<0.05.4.Correlations between ATG5 mRNA in PBMCs and SLEDAI as well as clinical manifestation:There were negatively correlations between ATG5level and SLEDAI(r=-0.292,P<0.05).The rate of SLE patients with proteinuria with the level of ATG5 mRNA<1.44 are higher than that in ATG5mRNA?1.44,as well as of the depression of C3 and C4,P<0.05.The SLEDAI scores of SLE patients with the level of ATG5 mRNA<1.44 was higher than SLE patients with the level of ATG5 mRNA?1.44,P<0.05.5.Correlations between LC3 mRNA in PBMCs SLEDAI as well as clinical manifestation:There were negatively correlations between LC3level and SLEDAI(r=-0.263,P<0.05).The level of LC3 mRNA in SLE patients with anti-dsDNA antibody positive was 0.45(0.67),lower than the SLE patients with anti-dsDNA antibody negative0.78(0.71),P<0.05.6.Correlations between Tecpr1 mRNA in PBMCs SLEDAI as well as clinical manifestation:There were negatively correlations between Tecpr1level and SLEDAI(r=-0.32,P<0.01).Conclusions1.The LC3-associated phagocytosis(LAP)related genes were decrease in PBMCs of SLE patients,but the canonical autophagy necessary gene WIPI2 was not,suggesting that LAP may contribute to the pathogenesis of SLE.2.The levels of LC3-associated phagocytosis related genes TIM4,Beclin1,ATG5,LC3 and Tecpr1 were connected with SLEDAI,as well as parts of clinical manifestation,suggesting that LAP play an important role in SLE development.