Astrocytes play an important role in the pathogenesis of bilirubin neurotoxicity, and activated astrocytes might be potential mediators of neuroinflammation processes contributing to neuronal cell death and tissue injury. Recent studies have reported that activated microglia induce two types of reactive astrocytes. A1 astrocytes could cause neuronal death and synaptic damage, as well as impaired phagocytosis. Therefore, the purpose of this study was to investigate whether unconjugated bilirubin (UCB)-induced A1-like astrocytes take on a neuroinflammation type and the underlying regulatory mechanisms. In this study, primary cortical astrocytes were treated with UCB in vitro. We detected the expression of complement component 3 (C3), S100 calcium binding protein A10 (S100A10), nuclear factor kappa B (NF-κB), NLR family pyrin domain containing 3 (NLRP3), activated caspase-1, gasdermin D N-terminal (GSDMD-N), PSD95, synaptophysin (SYP), the transcription levels of interleukin (IL)-1β and IL-18, and the survival rate of astrocytes after UCB treatment. The results showed that an increase in C3 was accompanied by a decrease in S100A10, and that A1-like astrocytes were functionally expressed after UCB stimulation. Meanwhile, the NF-κB and caspase-1 pathways were activated after UCB stimulation. After adding the NF-κB-specific inhibitor trans-activator of transcriptional-NEMO-binding domain (TAT-NBD) and caspase-1 specific inhibitor VX-765, the survival rate of astrocytes and neurons increased, whereas the protein expression of C3, NF-κB, NLRP3, activated caspase-1, and GSDMD-N decreased, and the mRNA levels of IL-1β and IL-18 reduced. Thus, we concluded that UCB stimulates the activation of A1-like astrocytes. Inhibition of NF-κB and caspase-1 alleviated A1-like astrocytes and exerted anti-inflammatory protective effects.

星形胶质细胞在胆红素神经毒性的发病机制中起重要作用，活化的星形胶质细胞可能是导致神经细胞死亡和组织损伤的神经炎症过程的潜在介质。最近的研究报告说，激活的小胶质细胞会诱导两种类型的反应性星形胶质细胞。A1 星形胶质细胞可导致神经元死亡和突触损伤，以及吞噬功能受损。因此，本研究的目的是研究未结合胆红素 (UCB) 诱导的 A1 样星形胶质细胞是否具有神经炎症类型和潜在的调节机制。在这项研究中，原代皮质星形胶质细胞在体外用 UCB 处理。我们检测了补体成分 3 (C3)、S100 钙结合蛋白 A10 (S100A10)、核因子 kappa B (NF-κB)、NLR 家族 pyrin 结构域包含 3 (NLRP3)、激活的 caspase-1、gasdermin D N-末端 (GSDMD-N)、PSD95、突触素 (SYP)、白细胞介素 (IL)-1β 和 IL-18 的转录水平，以及UCB治疗后星形胶质细胞的存活率。结果表明，C3 的增加伴随着 S100A10 的减少，并且 A1 样星形胶质细胞在 UCB 刺激后功能性表达。同时，UCB 刺激后激活了 NF-κB 和 caspase-1 通路。添加NF-κB特异性抑制剂转录-NEMO结合域反式激活因子（TAT-NBD）和caspase-1特异性抑制剂VX-765后，星形胶质细胞和神经元的存活率增加，而C3的蛋白表达， NF-κB、NLRP3、活化的caspase-1和GSDMD-N降低，IL-1β和IL-18的mRNA水平降低。因此，我们得出结论，UCB 刺激 A1 样星形胶质细胞的激活。抑制 NF-κB 和 caspase-1 可减轻 A1 样星形胶质细胞并发挥抗炎保护作用。