Takegawa Daisuke, Nakanishi Tadashi, Hirao Kouji, Yumoto Hiromichi, Takahashi Kanako, Matsuo Takashi
Department of Conservative Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
Department of Conservative Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
J Endod. 2014 Sep;40(9):1382-7. doi: 10.1016/j.joen.2014.03.018. Epub 2014 May 9.
Marked infiltration of inflammatory cells such as activated T cells producing interferon-γ (IFN-γ) is observed in severe pulpitis. However, the roles of IFN-γ in the innate immune response of dental pulp have not been reported. Indoleamine 2, 3-dioxygenase (IDO) is a regulator of immune responses, and the IDO expression is induced by IFN-γ in many cells whose expression in dental pulp is unknown. The purpose of this study was to determine the role of IFN-γ in the immune response through microbial pattern recognition receptors (PRRs) such as Toll-like receptors or nucleotide-binding oligomerization domain-like receptors on the production of proinflammatory cytokines such as CXCL10 and interleukin (IL)-6 and the expression of IDO in cultured human dental pulp cells (HDPCs).
HDPCs were established from explant cultures of healthy pulp tissues. CXCL10 and IL-6 production was determined using enzyme-linked immunosorbent assay. Confirmation of IDO localization in dental pulp tissues was examined using immunohistochemistry. IDO expression in HDPCs was analyzed by immunoblot.
IFN-γ significantly up-regulated CXCL10 and IL-6 production in the HDPCs stimulated with ligands for PRRs in a concentration-dependent manner. The expression of IDO was detected in inflamed pulp tissue. In addition, IFN-γ in combination with the PRR ligands enhanced IDO expression in HDPCs compared with IFN-γ alone. Moreover, CXCL10 production in IFN-γ-stimulated HDPCs was inhibited by an IDO inhibitor.
This study showed the synergistic effects by IFN-γ on cytokine production and IDO expression in HDPCs, suggesting that IFN-γ may modulate the innate immune response of dental pulp.
在严重牙髓炎中可观察到有大量炎性细胞浸润，如产生γ干扰素（IFN-γ）的活化T细胞。然而，IFN-γ在牙髓固有免疫反应中的作用尚未见报道。吲哚胺2,3-双加氧酶（IDO）是免疫反应的调节因子，在许多细胞中，IFN-γ可诱导IDO表达，而其在牙髓中的表达情况尚不清楚。本研究旨在确定IFN-γ通过Toll样受体或核苷酸结合寡聚化结构域样受体等微生物模式识别受体（PRRs）对促炎细胞因子如CXCL10和白细胞介素（IL）-6产生以及在培养的人牙髓细胞（HDPCs）中IDO表达的免疫反应中的作用。
从健康牙髓组织的外植体培养物中建立HDPCs。使用酶联免疫吸附测定法测定CXCL10和IL-6的产生。采用免疫组织化学法检查IDO在牙髓组织中的定位。通过免疫印迹分析HDPCs中IDO的表达。
IFN-γ以浓度依赖的方式显著上调PRRs配体刺激的HDPCs中CXCL10和IL-6的产生。在发炎的牙髓组织中检测到IDO的表达。此外，与单独使用IFN-γ相比，IFN-γ与PRR配体联合使用可增强HDPCs中IDO的表达。此外，IDO抑制剂可抑制IFN-γ刺激的HDPCs中CXCL10的产生。
本研究显示了IFN-γ对HDPCs中细胞因子产生和IDO表达的协同作用，表明IFN-γ可能调节牙髓的固有免疫反应。
