Kim Ji-Eun, Wang Su Hyeon, Lee Duk-Shin, Kim Tae-Hyun
Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chuncheon, 24252, Korea.
Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, 24252, Korea.
Sci Rep. 2025 Mar 6;15(1):7906. doi: 10.1038/s41598-025-92780-5.
P2X7 receptor (P2X7R) augments lipopolysaccharide (LPS)-toll-like receptor 4 (TLR4)-mediated neuroinflammation. These roles of P2X7R in neuroinflammation are relevant to nitrosative stress through nuclear factor-κB (NF-κB)-inducible nitric oxide synthase (iNOS) pathway, while the underlying mechanisms are largely unknown. In the present study, we investigated whether protein disulfide isomerase (PDI) is involved in the integration of TLR4-P2X7R functions in response to LPS in vivo. The present study showed that LPS elicited NF-κB-mediated PDI upregulation, iNOS induction and S-nitrosylated PDI (SNO-PDI) level, independent of S-nitrosylation of NF-κB p65 subunit, in P2X7R mice more than P2X7R mice. SN50 (an NF-κB inhibitor) effectively diminished LPS-induced PDI upregulation in both P2X7R and P2X7R mice. PDI knockdown attenuated LPS-induced p65 S276 phosphorylation and iNOS induction in both strains. Of interest, S-nitroso-N-acetyl-DL-penicillamine (SNAP, a NO donor) increased SNO-PDI level, surface P2X7R expression and p65 S276 phosphorylation in P2X7R mice under physiological condition. In P2X7R mice, SNAP was less effective on NF-κB S276 phosphorylation, although SNO-PDI level was similar to that in P2X7R mice. Taken together, the present data demonstrate that PDI may be an intermediator to integrate TLR4- and P2X7R-mediated signaling pathways in a positive feedback loop, which would exert NF-κB-iNOS-mediated nitrosative stress during LPS-induced neuroinflammation.
P2X7受体（P2X7R）增强脂多糖（LPS）-Toll样受体4（TLR4）介导的神经炎症。P2X7R在神经炎症中的这些作用通过核因子-κB（NF-κB）诱导型一氧化氮合酶（iNOS）途径与亚硝化应激相关，但其潜在机制在很大程度上尚不清楚。在本研究中，我们调查了蛋白二硫键异构酶（PDI）是否参与体内LPS刺激下TLR4-P2X7R功能的整合。本研究表明，与P2X7R基因敲除小鼠相比，LPS在P2X7R基因敲入小鼠中引起NF-κB介导的PDI上调、iNOS诱导和S-亚硝基化PDI（SNO-PDI）水平升高，且与NF-κB p65亚基的S-亚硝基化无关。SN50（一种NF-κB抑制剂）有效减少了LPS诱导的P2X7R基因敲除和P2X7R基因敲入小鼠的PDI上调。在两种品系中，敲低PDI均可减弱LPS诱导的p65 S276磷酸化和iNOS诱导。有趣的是，在生理条件下，S-亚硝基-N-乙酰-DL-青霉胺（SNAP，一种NO供体）增加了P2X7R基因敲入小鼠的SNO-PDI水平、表面P2X7R表达和p65 S276磷酸化。在P2X7R基因敲除小鼠中，尽管SNO-PDI水平与P2X7R基因敲入小鼠相似，但SNAP对NF-κB S276磷酸化的作用较小。综上所述，目前的数据表明，PDI可能是在正反馈回路中整合TLR4和P2X7R介导的信号通路的介质，这将在LPS诱导的神经炎症过程中产生NF-κB-iNOS介导的亚硝化应激。
