Exosomal Transfer of DNA Methyl-Transferase mRNA Induces an Immunosuppressive Phenotype in Human Monocytes.
Exosomal Transfer of DNA Methyl-Transferase mRNA Induces an Immunosuppressive Phenotype in Human Monocytes.
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DOI：
10.1097/shk.0000000000001928
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发表时间：
2022-06-01
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脓毒症的幸存者表现出持续的免疫抑制。表观遗传事件可能是这些免疫抑制变化中的一些原因。在脓毒症过程中，循环外切体含有大量的DNA甲基转移酶(DNMT)mRNAs。我们假设，外切体直接将DNMT mRNAs转移到受体单核细胞，从而导致甲基化事件和免疫抑制。用脂多糖刺激单核细胞产生含有DNMT基因的外切体。共聚焦显微镜被用来确定存在药物抑制时的摄取动力学。利用DNMT siRNAs调控特异性DNMT基因的表达和包装。用亚硫酸氢盐测序评估全基因组和基因特异性甲基化。通过独创性途径分析，确定差异甲基化区域的生物学功能意义。外切体能有效地将DNMT基因转移到受体单核细胞。药物抑制外切体摄取可阻止DNMT基因表达的增加。受体单核细胞出现高甲基化改变和基因抑制。SiRNAs减少了DNMTmRNAs的包装，阻止了肿瘤坏死因子α基因的抑制，恢复了免疫活性。这些数据支持外切体介导的DNMT基因转移及其甲基化和基因沉默的作用。药物摄取抑制或靶向siRNA介导的DNMT基因沉默可阻止DNMT基因转移，并维持细胞表达肿瘤坏死因子α的能力。这突出了靶向这些外切体介导的表观遗传事件以在脓毒症期间维持宿主免疫反应的潜在治疗价值。
Survivors of sepsis exhibit persistent immunosuppression. Epigenetic events may be responsible for some of these immunosuppressive changes. During sepsis circulating exosomes contain large quantities of DNA methyltransferase (DNMT) mRNAs. We hypothesized that exosomes directly transfer DNMT mRNAs to recipient monocytes with resultant methylation events and immunosuppression. Exosomes containing DNMT mRNA were generated by stimulating monocytes with LPS. Confocal microscopy was used to determine uptake kinetics in the presence of pharmacologic inhibition. Expression and packaging of specific DNMT mRNA was controlled using DNMT siRNAs. Whole genome and gene specific methylation was assessed using bisulfite sequencing. Ingenuity pathway analysis was performed to determine the biological function of significance of differentially methylated regions. Exosomes effectively transferred DNMT mRNA to recipient monocytes. Pharmacologic inhibition of exosome uptake prevented this increase in DNMT mRNA expression. Recipient monocytes exhibited hypermethylation changes and gene suppression. siRNAs decreased the packaging of DNMT mRNAs and prevented TNFα gene suppression, restoring immunocompetence. These data support a role for exosome-mediated transfer of DNMT mRNA with resultant methylation and gene silencing. Pharmacologic uptake inhibition or targeted siRNA mediated DNMT gene silencing prevented DNMT mRNA transfer and maintained the cell’s ability to express TNFα in response to LPS. This highlights the potential therapeutic value of targeting these exosome-mediated epigenetic events to maintain the host immune response during sepsis.