Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
Department of Oral Medicine and Surgery, Jordan University of Science and Technology, Irbid, Jordan.
Int Endod J. 2023 Feb;56(2):193-202. doi: 10.1111/iej.13855. Epub 2022 Nov 12.
To evaluate the expression and function of the nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome in caries induced pulpitis.
NLRP3 expression was determined with immunohistochemistry in the dental pulp and qPCR in dental pulp cells (DPCs). THP-1 macrophages expressing the apoptosis-related speck-like protein (ASC) and green fluorescent protein (GFP) fusion protein were used to assess NLRP3 inflammasome activation by live cell imaging, following treatment with lipopolysaccharide (LPS) and lipoteichoic acid (LTA). Caspase I inhibitor was used to confirm inflammasome activation. An ex-vivo pulpitis model in which the DPCs were co-cultured with THP-1 macrophages was used to study the effect of the NLRP3 inflammasome inhibitor (MCC950), and cytokines were measured using ELISA and multiplex array. Data were analysed using the t-test or anova followed by a Bonferroni post hoc test with the level of significance set at p ≤ .05.
NLRP3 inflammasome was differentially expressed in dental pulp of sound and carious teeth. Treatment of DPCs with LTA significantly upregulates NLRP3 and IL-1 β-expression (p < .05) and in induces more ASC specks formation compared to LPS. IL-β release in response to LTA treatment is significantly reduced with Caspase I inhibitor suggesting inflammasome dependent mechanism (p < .01). NLRP3-specific inhibitor, MCC950, significantly reduced IL-1β and IL-6 in an ex-vivo pulpitis model (p < .01) but had no effect on IL-8 or matrix metalloproteinase-9 (MMP-9).
Expression and upregulation of NLRP3 inflammasome with caries and LTA treatment suggest a role in caries-induced pulpitis. NLRP3 inhibitor attenuated the release of selective inflammatory cytokines and could be a potential treatment target that merit further investigation.
评估富含核苷酸结合寡聚化结构域样受体蛋白 3（NLRP3）炎性小体在龋源性牙髓炎中的表达和功能。
采用免疫组织化学法检测牙髓中 NLRP3 的表达，采用 qPCR 法检测牙髓细胞（DPC）中 NLRP3 的表达。使用表达凋亡相关斑点样蛋白（ASC）和绿色荧光蛋白（GFP）融合蛋白的 THP-1 巨噬细胞，通过活细胞成像评估脂多糖（LPS）和脂磷壁酸（LTA）处理后 NLRP3 炎性小体的激活情况。使用 caspase I 抑制剂来确认炎性小体的激活。采用 DPC 与 THP-1 巨噬细胞共培养的离体牙髓炎模型，研究 NLRP3 炎性小体抑制剂（MCC950）的作用，并用 ELISA 和多重分析来检测细胞因子。使用 t 检验或方差分析，然后用 Bonferroni 事后检验，p 值设定为 p ≤ .05。
NLRP3 炎性小体在正常和龋坏牙齿的牙髓中呈差异表达。LTA 处理 DPC 可显著上调 NLRP3 和 IL-1β 的表达（p < .05），并诱导 ASC 斑点形成增多，与 LPS 相比。用 caspase I 抑制剂处理后，LTA 诱导的 IL-β 释放明显减少，提示存在炎性小体依赖性机制（p < .01）。NLRP3 特异性抑制剂 MCC950 可显著减少离体牙髓炎模型中 IL-1β 和 IL-6 的释放（p < .01），但对 IL-8 或基质金属蛋白酶-9（MMP-9）无影响。
NLRP3 炎性小体在龋病和 LTA 处理后的表达和上调提示其在龋源性牙髓炎中的作用。NLRP3 抑制剂可减轻选择性炎症细胞因子的释放，可能是一种有潜力的治疗靶点，值得进一步研究。
