Sakuma Chisato, Takenouchi Takato, Sato Mitsuru
Silkworm Research Group, Division of Silk-Producing Insect Biotechnology, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8634, Japan.
Animal Model Development Group, Division of Biomaterial Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8634, Japan.
Int J Mol Sci. 2025 Jan 29;26(3):1178. doi: 10.3390/ijms26031178.
The P2X7 receptor is involved in innate immune responses, with its intracellular C-terminal domain capable of interacting with signaling molecules to regulate immune cell activation; however, the mechanisms underlying the signaling complexes remain unclear. To elucidate the function of the P2X7 C-terminal domain, we established bone marrow-derived macrophage (BMDM) cell lines from transgenic (Tg) mice overexpressing the C-terminal domain of P2X7 or anti-P2X7 C-terminal domain single-chain variable fragment (scFv) intrabody. In contrast to wild-type mouse BMDMs, the Tg BMDMs showed impairment of inflammatory responses induced by lipopolysaccharide (LPS) stimulation, such as NF-κB activation and subsequent TNF-α, IL-1β, and IL-6 expression. Furthermore, P2X7 was specifically associated with myeloid differentiation primary response gene 88 (MyD88) in wild-type BMDMs; its specific interaction was strongly interfered with by overexpression of the P2X7 C-terminal domain or anti-P2X7 C-terminal domain scFv in Tg BMDMs. These observations strongly suggest that P2X7 may have pivotal roles in LPS signaling cascades and could modulate macrophage inflammatory responses through its C-terminal domain.
P2X7受体参与先天免疫反应，其细胞内C末端结构域能够与信号分子相互作用以调节免疫细胞激活；然而，信号复合物背后的机制仍不清楚。为了阐明P2X7 C末端结构域的功能，我们从过表达P2X7 C末端结构域的转基因（Tg）小鼠或抗P2X7 C末端结构域单链可变片段（scFv）胞内抗体建立了骨髓来源的巨噬细胞（BMDM）细胞系。与野生型小鼠BMDM不同，Tg BMDM显示出脂多糖（LPS）刺激诱导的炎症反应受损，如NF-κB激活以及随后的TNF-α、IL-1β和IL-6表达。此外，P2X7在野生型BMDM中与髓样分化初级反应基因88（MyD88）特异性相关；在Tg BMDM中，P2X7 C末端结构域或抗P2X7 C末端结构域scFv的过表达强烈干扰了其特异性相互作用。这些观察结果强烈表明，P2X7可能在LPS信号级联反应中起关键作用，并可能通过其C末端结构域调节巨噬细胞炎症反应。
