| BackgroundSystemic lupus erythematosus（SLE）is an autoimmune disease characterized by multiple autoantibodies production,inflammatory cell infiltration,and multiple organ damage.The etiology and mechanism of SLE has not been fully elucidated.Studies have proved that environmental factors,genetic factors,and autoimmune regulatory disorders may be involved in the occurrence and development of SLE.However,none of this evidence can fully elucidate the disease characteristics of SLE.N6-methyladenosine（m6A）is a rich form of chemical modification on eukaryotic m RNA.The m6 A modification is dynamically reversible,mainly dependent on methyltransferase and demethylase,and can be involved in various physiological and pathological processes,including autoimmune diseases,by participating in the expression,shearing,transport,and stability of RNA.However,whether m6 A plays a role in the disease course of SLE remains unknown.ObjectiveTo compare the expression of m6 A demethylase in peripheral blood mononuclear cell（PBMC）and T lymphocytes in SLE patients and healthy controls and investigate the effect of m6 A demethylase on T lymphocyte function.MethodsA total of 107 SLE patients and 111 healthy controls were enrolled in this study.The expression level of demethylase in PBMC was investigated by quantitative real-time polymerase chain reaction and western blot assay.Another 32 SLE patients and 32 healthy controls were enrolled to further study the expression level of demethylase in T lymphocytes.A self-made questionnaire was used to collect general demographic information and clinical data of SLE patients.Epi Data 3.1 software was used to input the questionnaire.SPSS 23.0 software and Graph Pad Prism 8.0 software were used for statistical analysis and mapping.Flow Jo 7.6 software was used to analyze flow cytometry detection data.Then,we further used the lentivirus overexpression vector and Jurkat cells to realize the overexpression of demethylase in T lymphocytes to explore the effect of demethylase on T lymphocyte function.ResultsCompared with PBMC of the control group,the expression level of FTO m RNA in PBMC was downregulated in SLE patients（Z =-4.800,P < 0.001）.The association analysis results showed that the expression of FTO m RNA in PBMC was decreased in SLE patients in the anti-histone antibody-positive group compared with those in the antihistone antibody-negative group（Z =-2.167,P = 0.028）.There was no association between FTO and quantitative clinical indicators or clinical medication（all P > 0.05）.The m RNA and protein levels of ALKBH5 were downregulated in PBMC and T lymphocytes of SLE patients（all P < 0.05）.In PBMC,ALKBH5 m RNA level increased in SLE patients with high anti-double-strand DNA antibody levels（Z=-2.201,P = 0.028）,and ALKBH5 m RNA level was negatively correlated with complement C4 level and glucocorticoid dose（all P < 0.05）;Compared with SLE patients with a low dose of glucocorticoids,the ALKBH5 expression level in SLE patients with medium and high dose of glucocorticoids was decreased（Z =-2.206,P = 0.027）.In T lymphocytes,ALKBH5 m RNA levels were reduced in SLE patients with low complement levels,positive anti-double-stranded DNA antibody,positive anti-Smith antibody,positive antiribonucleoprotein antibody,and positive proteinuria（all P < 0.05）.The m RNA expression level of ALKBH5 was negatively correlated with SLE activity index score,glucocorticoid dose,erythrocyte sedimentation rate,and anti-double-stranded DNA antibody level,and was positively correlated with complement C3 and C4（all P < 0.05）.The results of the cell function experiment showed that ALKBH5 overexpression could promote the apoptosis of T lymphocytes and inhibit the proliferation of T lymphocytes（all P < 0.05）.ConclusionsThe expressions of m6 A demethylase in SLE cases were downregulated,and m6 A demethylases were associated with SLE.The low expression of ALKBH5 may be involved in the development of SLE by inhibiting the apoptosis of T lymphocytes and promoting the proliferation of T lymphocytes. |
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