背景:牙根表面的成牙骨质是牙骨质形成(牙骨质生成)的原因,对牙龈卟啉单胞菌刺激敏感。我们先前已证明转录因子CXXC型锌指蛋白5(CXXC5)参与牙骨质形成。这里,我们旨在从线粒体生物发生的角度阐明CXXC5调节牙龈卟啉单胞菌抑制骨水泥生成的机制.
方法:体内,牙髓暴露导致小鼠下颌第一磨牙根尖周病变,牙龈卟啉单胞菌被应用于根管。体外,诱导成牙骨质细胞细胞系(OCCM-30),并提交RNA测序。将这些细胞与牙龈卟啉单胞菌共培养,并检查成骨能力和线粒体生物发生。通过慢病毒转导构建稳定的CXXC5过表达的细胞,通过siRNA转染下调PGC-1α(线粒体生物发生的中心诱导物)。
结果:根尖周围病变扩大,牙龈卟啉单胞菌治疗降低了PGC-1α的表达。根尖炎症时,Cxxc5表达随着Il-6上调而降低。RNA测序显示成骨标志物的表达增强,Cxxc5和牙骨质形成过程中的线粒体生物发生标记。牙龈卟啉单胞菌抑制成骨能力,线粒体生物发生标记,线粒体(mt)DNA拷贝数,和成牙骨质细胞的ATP含量,而CXXC5过表达拯救了这些效应。PGC-1α敲低显著损害成牙骨质细胞分化,证实线粒体生物发生在骨水泥发生中的作用。
结论:CXXC5是一种牙龈卟啉单胞菌敏感的转录因子,通过影响PGC-1α依赖的线粒体生物发生来正向调节牙骨质生成。视频摘要。
Cementoblasts on the tooth-root surface are responsible for cementum formation (
cementogenesis) and sensitive to Porphyromonas gingivalis stimulation. We have previously proved transcription factor CXXC-type zinc finger protein 5 (CXXC5) participates in
cementogenesis. Here, we aimed to elucidate the mechanism in which CXXC5 regulates P. gingivalis-inhibited
cementogenesis from the perspective of mitochondrial biogenesis.
In vivo, periapical lesions were induced in mouse mandibular first molars by pulp exposure, and P. gingivalis was applied into the root canals. In vitro, a cementoblast cell line (OCCM-30) was induced
cementogenesis and submitted for RNA sequencing. These cells were co-cultured with P. gingivalis and examined for osteogenic ability and mitochondrial biogenesis. Cells with stable CXXC5 overexpression were constructed by lentivirus transduction, and PGC-1α (central inducer of mitochondrial biogenesis) was down-regulated by siRNA transfection.
Periapical lesions were enlarged, and PGC-1α expression was reduced by P. gingivalis treatment. Upon apical inflammation, Cxxc5 expression decreased with Il-6 upregulation. RNA sequencing showed enhanced expression of osteogenic markers, Cxxc5, and mitochondrial biogenesis markers during cementogenesis. P. gingivalis suppressed osteogenic capacities, mitochondrial biogenesis markers, mitochondrial (mt)DNA copy number, and cellular ATP content of cementoblasts, whereas CXXC5 overexpression rescued these effects. PGC-1α knockdown dramatically impaired cementoblast differentiation, confirming the role of mitochondrial biogenesis on cementogenesis.
CXXC5 is a P. gingivalis-sensitive transcription factor that positively regulates
cementogenesis by influencing PGC-1α-dependent mitochondrial biogenesis. Video Abstract.