Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary.
Br J Pharmacol. 2024 Sep;181(17):3246-3262. doi: 10.1111/bph.16386. Epub 2024 May 14.
Pulpitis is associated with tooth hypersensitivity and results in pulpal damage. Thermosensitive transient receptor potential (TRP) ion channels expressed in the dental pulp may be key transducers of inflammation and nociception. We aimed at investigating the expression and role of thermo-TRPs in primary human dental pulp cells (hDPCs) in normal and inflammatory conditions.
Inflammatory conditions were induced in hDPC cultures by applying polyinosinic:polycytidylic acid (poly(I:C)). Gene expression and pro-inflammatory cytokine release were measured by RT-qPCR and ELISA. Functions of TRPA1 channels were investigated by monitoring changes in intracellular Ca concentration. Mitochondrial superoxide production was measured using a fluorescent substrate. Cellular viability was assessed by measuring the activity of mitochondrial dehydrogenases and cytoplasmic esterases. TRPA1 activity was modified by agonists, antagonists, and gene silencing.
Transcripts of TRPV1, TRPV2, TRPV4, TRPC5, and TRPA1 were highly expressed in control hDPCs, whereas TRPV3, TRPM2, and TRPM3 expressions were much lower, and TRPM8 was not detected. Poly(I:C) markedly up-regulated TRPA1 but not other thermo-TRPs. TRPA1 agonist-induced Ca signals were highly potentiated in inflammatory conditions. Poly(I:C)-treated cells displayed increased Ca responses to HO, which was abolished by TRPA1 antagonists. Inflammatory conditions induced oxidative stress, stimulated mitochondrial superoxide production, resulted in mitochondrial damage, and decreased cellular viability of hDPCs. This inflammatory cellular damage was partly prevented by the co-application of TRPA1 antagonist or TRPA1 silencing.
Pharmacological blockade of TRPA1 channels may be a promising therapeutic approach to alleviate pulpitis and inflammation-associated pulpal damage.
牙髓炎与牙本质过敏症相关，可导致牙髓损伤。牙髓中表达的热敏瞬时受体电位（TRP）离子通道可能是炎症和痛觉传导的关键转导器。本研究旨在探讨热敏感 TRP 在正常和炎症状态下人牙髓细胞（hDPC）中的表达和作用。
通过polyinosinic:polycytidylic acid（poly(I:C)）在 hDPC 培养物中诱导炎症状态。通过 RT-qPCR 和 ELISA 测量基因表达和促炎细胞因子的释放。通过监测细胞内 Ca 浓度的变化来研究 TRPA1 通道的功能。使用荧光底物测量线粒体超氧化物的产生。通过测量线粒体脱氢酶和细胞质酯酶的活性来评估细胞活力。通过激动剂、拮抗剂和基因沉默来修饰 TRPA1 活性。
TRPV1、TRPV2、TRPV4、TRPC5 和 TRPA1 的转录本在对照 hDPC 中高度表达，而 TRPV3、TRPM2 和 TRPM3 的表达水平较低，TRPM8 则未检测到。poly(I:C) 显著上调了 TRPA1，但没有上调其他热敏 TRP。在炎症条件下，TRPA1 激动剂诱导的 Ca 信号显著增强。用 TRPA1 拮抗剂处理可消除 poly(I:C)处理的细胞对 HO 的 Ca 反应。炎性条件诱导氧化应激，刺激线粒体超氧化物的产生，导致线粒体损伤，并降低 hDPC 的细胞活力。TRPA1 拮抗剂或 TRPA1 沉默的共同应用部分预防了这种炎症性细胞损伤。
TRPA1 通道的药理学阻断可能是一种有前途的治疗方法，可减轻牙髓炎和炎症相关的牙髓损伤。
