巨噬细胞极化是牙周炎病理进程的核心调控机制[1]。在牙周炎微环境中,病原体相关分子模式通过激活Toll样受体等信号通路诱导巨噬细胞向促炎型M1极化,进而分泌 IL-1β、TNF-α 等炎症因子,加剧牙槽骨吸收[2]。近年研究发现,代谢重编程是调控极化的关键,例如糖酵解增强可促进 M1 极化,而氧化磷酸化主导 M2 表型[3, 4]。国内团队通过单细胞测序证实,巨噬细胞的糖酵解异常与炎症表型存在时空关联,尤其在铁代谢失衡模型中观察到糖酵解活性升高与纤维化进展的同步性[5]。这一发现提示代谢失衡可能通过表观遗传修饰影响免疫细胞功能[6],而甲酰肽受体1( FPR1 )作为连接代谢与免疫的关键分子[7],其作用机制亟待深入探究。
FPR1 作为 G 蛋白偶联受体家族成员,在炎症与代谢调控中具有双重功能[7, 8]。研究表明, FPR1 通过识别病原体甲酰肽激活 p38 MAPK/ERK 信号轴,触发 NADPH 氧化酶依赖性 ROS 爆发,驱动中性粒细胞趋化迁移并经由 ROS-NLRP3 轴促进 IL-1β/IL-6 等促炎因子释放[9]。值得注意的是, FPR1 与脂质代谢关键酶 SCAD (短链酰基辅酶A脱氢酶)的交互作用可通过 FPR1-hnRNP U-GR (异质核糖核蛋白U-糖皮质激素受体)复合体激活 SCAD 的转录活性,从而增强肝细胞线粒体 β 氧化能力,改善能量代谢稳态并缓解肝脏脂质沉积[10]。尽管目前尚未明确揭示 FPR1 对糖酵解的直接调控机制,但同家族的 FPR2 已被证实通过 Nox2/ROS/HIF-1α 信号轴增强丙酮酸脱氢酶( PDH )活性,从而促进葡萄糖的有氧代谢[11]。同时, FPR2 通过 mTORC1/SP1-FOXM1 通路将葡萄糖和谷氨酰胺重定向至核苷酸与脂肪酸合成等合成代谢途径,驱动肺癌细胞增殖[12]。这一发现为FPR1在巨噬细胞中通过代谢重编程(如糖酵解激活与乳酸化修饰)调控免疫表型(如 M1 极化)的潜在作用提供了跨受体功能类比依据。此外, FPR1 功能异常(如348T/T 基因型)通过趋化信号缺陷导致中性粒细胞迁移受阻,引发细菌定植及慢性炎症累积,最终加剧牙周组织破坏[13]。
糖酵解衍生的乳酸不仅是能量代谢产物,还可通过组蛋白乳酸化修饰调控基因转录[14]。瓦博格效应(有氧糖酵解)是炎症性巨噬细胞的代谢标志,其关键酶 HK2 和LDHA 的高表达显著增加乳酸生成。研究证实,乳酸既可通过组蛋白H3K18位点的乳酸化修饰增强 Arg1 等基因表达,驱动巨噬细胞向 M2 表型极化[15],也可能直接通过MAVS 蛋白促进 NLRP3 寡聚化,并通过乳酸化修饰调控炎症基因表达,进而使巨噬细胞向 M1 表型极化[16]。在肿瘤微环境中,乳酸化修饰已被证实可重塑巨噬细胞表型,形成免疫抑制微环境[17]。国内学者在病毒研究中发现,宿主细胞糖酵解为病毒复制提供原料,同时代谢产物可能通过表观遗传机制调控免疫应答,这一发现为牙周炎中代谢-表观遗传交互网络的研究提供了新视角[18]。
牙周炎的病理特征与巨噬细胞极化失衡密切相关。动物模型显示,高糖酵解活性的巨噬细胞通过分泌 IL-6、RANKL 等因子激活破骨细胞,加速牙槽骨流失[19]。近期提出的“代谢-表观遗传”轴概念强调,糖酵解衍生的乳酸可通过乳酸化修饰改变染色质可及性,进而调控极化相关基因(如 IRF5、PPARγ )的表达[20]。例如, HIF-1α 通过上调糖酵解酶表达促进乳酸生成,同时增强组蛋白乳酸化修饰,形成正向反馈环路[21]。然而, FPR1 是否参与这一调控网络仍属未知。
当前研究仍存在显著空白。首先, FPR1 与糖酵解的具体关联机制需进一步验证,例如其是否通过 PI3K/Akt或MAPK 通路调控葡萄糖摄取及乳酸生成。其次,牙周炎不同阶段的乳酸化修饰位点差异尚未解析,而 FPR1 的表达动态是否影响修饰位点的时空特异性值得探讨。此外,靶向代谢重编程的治疗策略(如二甲双胍或天然化合物芦丁)在牙周炎中的应用潜力待验证。国内研究显示,芦丁通过调控 Pcbp1 抑制巨噬细胞铁死亡,但其是否通过 FPR1 影响糖酵解-乳酸化轴仍需实验支持。
综上所述, FPR1 在巨噬细胞代谢重编程与表观遗传修饰中的双重作用为牙周炎研究提供了新方向。未来需整合单细胞测序、代谢组学及表观遗传编辑技术,阐明 FPR1 -糖酵解-乳酸化修饰轴的具体机制,为开发靶向代谢免疫调节的牙周治疗策略奠定理论基础。
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