Department of Medical Service, The Affiliated Nanhua Hospital of University of South China, Hengyang, 421002, Hunan Province, People's Republic of China.
Health school of Nuclear Indutrsy, Hengyang, 421002, Hunan Province, People's Republic of China.
Metab Brain Dis. 2022 Aug;37(6):1803-1813. doi: 10.1007/s11011-022-01017-1. Epub 2022 Jun 15.
Sepsis-associated encephalopathy (SAE) is a severe complication of sepsis. It has been reported that miR-25-3p is closely related to the development of sepsis. However, the detailed mechanism of miR-25-3p in SAE requires further investigation. Caecum ligation and puncture (CLP) was performed to induce SAE in vivo. LPS stimulation was applied to mimic the in vitro inflammatory model. The expression levels of TLR4 and NLRP3 in the cerebral cortex were evaluated by immunofluorescence. The gene and protein expression levels were determined by qRT-PCR and a western blot analysis. ELISA was used to detect the levels of inflammatory cytokines. The interaction between miR-25-3p and TLR4 was validated by a dual luciferase reporter assay. TLR4 and NLRP3 were highly expressed in the cerebral cortex of SAE mice, while miR-25-3p was expressed at low levels. Activation of the inflammasome, increased release of cytokines and microglial activation were also observed in the SAE mouse model. The overexpression of miR-25-3p inhibited the expression of LPS-induced cytokines and microglial activation. Furthermore, miR-25-3p inhibited TLR4 expression by directly targeting TLR4. The anti-inflammatory effect of miR-25-3p in LPS-induced CHME5 was reversed by TLR4 overexpression. miR-25-3p overexpression attenuated the activation of microglia in SAE by inhibiting the NLRP3/IL-1β/IL-18 axis by directly targeting TLR4, suggesting that miR-25-3p may be a potential target for SAE diagnosis and treatment.
脓毒症相关性脑病 (SAE) 是脓毒症的严重并发症。有报道称，miR-25-3p 与脓毒症的发生密切相关。然而，miR-25-3p 在 SAE 中的详细机制仍需进一步研究。本研究通过盲肠结扎穿孔（CLP）建立 SAE 动物模型，应用脂多糖（LPS）刺激建立体外炎症模型，免疫荧光法检测大脑皮质 TLR4 和 NLRP3 的表达水平，qRT-PCR 和 Western blot 检测 TLR4、NLRP3 基因和蛋白的表达水平，ELISA 检测炎症细胞因子的水平，双荧光素酶报告基因实验验证 miR-25-3p 与 TLR4 的靶向关系。结果表明，SAE 小鼠大脑皮质 TLR4 和 NLRP3 表达升高，miR-25-3p 表达降低，炎症小体激活，细胞因子释放增加，小胶质细胞活化。过表达 miR-25-3p 可抑制 LPS 诱导的炎症细胞因子和小胶质细胞的活化。此外，miR-25-3p 通过直接靶向 TLR4 抑制 TLR4 的表达。TLR4 过表达逆转了 miR-25-3p 对 LPS 诱导的 CHME5 抗炎作用。miR-25-3p 通过直接靶向 TLR4 抑制 NLRP3/IL-1β/IL-18 轴，从而减轻 SAE 中小胶质细胞的激活，提示 miR-25-3p 可能是 SAE 诊断和治疗的潜在靶点。
