Department of Preventive and Restorative Dentistry, Aracatuba School of Dentistry, São Paulo State University (UNESP), Araçatuba, Brazil.
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil.
Int Endod J. 2021 Jun;54(6):834-847. doi: 10.1111/iej.13480. Epub 2021 Feb 17.
To quantitatively and qualitatively compare the host proteomic profile in samples of symptomatic and asymptomatic apical periodontitis (AP) using nano-liquid chromatography-electron spray tandem mass spectrometry.
Samples were obtained from 18 patients with radiographically evident AP, divided into symptomatic and asymptomatic groups (nine per group) according to clinical characteristics. After sample collection, protein extraction, purification and quantification of the samples were performed, which were analysed by reverse-phase liquid chromatography coupled to mass spectrometry. Label-free quantitative proteomic analysis was performed by Protein Lynx Global Service software. Differences in expression of proteins between the groups were calculated using the Monte Carlo algorithm, considering P < 0.05 for down-regulated proteins and 1 - P > 0.95 for up-regulated proteins. Proteins were identified with the embedded ion accounting algorithm in the software and a search of the Homo sapiens UniProt database.
A total of 853 individual human proteins were identified. In the quantitative analysis, common proteins to both groups accounted for 143 proteins. Differences in expression between groups resulted in 51 up-regulated proteins (1 - P > 0.95) in the symptomatic group, including alpha-1-antitrypsin, protein S100-A8, myeloperoxidase, peroxiredoxin and lactotransferrin. This group also had 43 down-regulated proteins (P < 0.05), comprising immunoglobulin, neutrophil defensin, pyruvate kinase and alpha-enolase. The qualitative analysis considered only the exclusive proteins of each group. For the symptomatic group, 318 complete proteins and 29 fragments were identified, such as dedicator of cytokinesis protein, intersectin, prostaglandin, phospholipase DDHD2 and superoxide dismutase. For the asymptomatic group, 326 complete proteins and 37 fragments were identified, including azurocidin, C-reactive protein, collagen alpha, cathepsin, heat shock and laminin.
Quantitative differences in the expression of common proteins in cases of symptomatic and asymptomatic AP were found, which were mostly related to host immune response in both groups. Exclusive proteins in the symptomatic group were mainly related to the host response to the presence of viruses in endodontic infections, oxidative stress and proteolytic enzymes. The results provide a basis for a better understanding of cellular and molecular pathways involved in AP, establishing specific proteomic profiles for symptomatic and asymptomatic conditions.
使用纳升液相色谱-电喷雾串联质谱法定量和定性比较有症状和无症状根尖周炎（AP）样本中的宿主蛋白质组谱。
根据临床特征，将 18 名影像学显示有 AP 的患者分为有症状和无症状两组（每组 9 名），分别从这些患者中获取样本。样本采集后，进行蛋白质提取、纯化和定量，然后通过反相液相色谱与质谱联用进行分析。采用 Protein Lynx Global Service 软件进行无标记定量蛋白质组学分析。使用蒙特卡罗算法计算组间蛋白质表达差异，下调蛋白的 P 值<0.05，上调蛋白的 1-P>0.95。使用软件中嵌入的离子计数算法和 Homo sapiens UniProt 数据库对蛋白质进行鉴定。
共鉴定出 853 个人类蛋白质。在定量分析中，两组共有的蛋白质有 143 种。组间表达差异导致有症状组有 51 种上调蛋白（1-P>0.95），包括α-1-抗胰蛋白酶、S100-A8 蛋白、髓过氧化物酶、过氧化物还原酶和乳转铁蛋白。该组还有 43 种下调蛋白（P<0.05），包括免疫球蛋白、中性粒细胞防御素、丙酮酸激酶和α-烯醇酶。定性分析仅考虑每组独有的蛋白质。对于有症状组，鉴定出 318 种完整蛋白和 29 种片段，如细胞分裂蛋白 dedicator、连接蛋白 intersectin、前列腺素、DDHD2 磷脂酶和超氧化物歧化酶。对于无症状组，鉴定出 326 种完整蛋白和 37 种片段，包括尿嘧啶蛋白、C 反应蛋白、胶原蛋白α、组织蛋白酶、热休克蛋白和层粘连蛋白。
发现有症状和无症状 AP 患者常见蛋白表达存在定量差异，这主要与两组的宿主免疫反应有关。有症状组独有的蛋白质主要与牙髓感染中病毒的存在、氧化应激和蛋白水解酶有关。研究结果为更好地了解 AP 涉及的细胞和分子途径提供了依据，为有症状和无症状情况建立了特定的蛋白质组学特征。
