Aggregatibacter actinomycetemcomitans outer membrane protein 29 (Omp29) induces TGF-β-regulated apoptosis signal in human gingival epithelial cells via fibronectin/integrinβ1/FAK cascade.
Aggregatibacter actinomycetemcomitans outer membrane protein 29 (Omp29) induces TGF-β-regulated apoptosis signal in human gingival epithelial cells via fibronectin/integrinβ1/FAK cascade.
复制标题
放线菌聚集菌外膜蛋白 29 (Omp29) 通过纤连蛋白/整合素β1/FAK 级联诱导人牙龈上皮细胞中 TGF-β 调节的凋亡信号。
DOI：
10.1111/cmi.12607
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发表时间：
2016
影响因子：
3.4
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
Yoshimoto T.;et al
牙周病细菌引起的牙龈结膜上皮细胞凋亡可加重牙周炎。这种病理性凋亡与转化生长因子β (TGF - β)的激活有关。然而，微生物诱导TGF - β活化的分子机制尚不清楚。我们之前报道过放线菌聚合杆菌（aggregatibacter actinomycetemcomitans, Aa）激活TGF - β受体(TGF - β r)/smad2信号传导，诱导上皮细胞凋亡，尽管Aa不能与TGF - β r结合。此外，aaomps家族成员外膜蛋白29kda （Omp29）可通过focal adhesion kinase （FAK）信号传导诱导肌动蛋白重排，FAK也通过与整合素合作激活TGF - β。因此，我们假设Omp29通过FAK活性诱导的肌动蛋白重排会增强TGF - β的激活，导致体外牙龈上皮细胞凋亡。通过人牙龈上皮细胞系OBA9，我们发现Omp29激活TGF - β r /smad2信号通路，降低细胞培养的细胞外基质（ECM）中活性TGF - β蛋白水平，提示TGF - β r被反激活。通过细胞松弛素D或blebbistatin抑制肌动蛋白重排和siRNA转染降低FAK或整合素β1表达，可减弱Omp29引起的ECM中TGF - β r /smad2信号活性和TGF - β水平的降低。此外，Omp29结合纤维连接蛋白（Fn）诱导其聚集在整合素β1上，这与TGF‐β信号传导活性有关。所有化学抑制剂和sirna均可阻断Omp29诱导的OBA9细胞凋亡。这些结果表明，Omp29与Fn结合以促进Fn/整合素β1/FAK信号依赖性TGF - β从ECM中释放，从而通过TGF - β r /smad2途径诱导牙龈上皮细胞凋亡。
Gingival junctional epithelial cell apoptosis caused by periodontopathic bacteria exacerbates periodontitis. This pathological apoptosis is involved in the activation of transforming growth factor β (TGF‐β). However, the molecular mechanisms by which microbes induce the activation of TGF‐β remain unclear. We previously reported thatAggregatibacter actinomycetemcomitans(Aa) activated TGF‐β receptor (TGF‐βR)/smad2 signalling to induce epithelial cell apoptosis, even thoughAacannot bind to TGF‐βR. Additionally, outer membrane protein 29 kDa (Omp29), a member of theAaOmps family, can induce actin rearrangements via focal adhesion kinase (FAK) signalling, which also plays a role in the activation of TGF‐β by cooperating with integrin. Accordingly, we hypothesized that Omp29‐induced actin rearrangements via FAK activity would enhance the activation of TGF‐β, leading to gingival epithelial cell apoptosisin vitro. By using human gingival epithelial cell line OBA9, we found that Omp29 activated TGF‐βR/smad2 signalling and decreased active TGF‐β protein levels in the extracellular matrix (ECM) of cell culture, suggesting the transactivation of TGF‐βR. Inhibition of actin rearrangements by cytochalasin D or blebbistatin and knockdown of FAK or integrinβ1 expression by siRNA transfection attenuated TGF‐βR/smad2 signalling activity and reduction of TGF‐β levels in the ECM caused by Omp29. Furthermore, Omp29 bound to fibronectin (Fn) to induce its aggregation on integrinβ1, which is associated with TGF‐β signalling activity. All the chemical inhibitors and siRNAs tested blocked Omp29‐induced OBA9 cells apoptosis. These results suggest that Omp29 binds to Fn in order to facilitate Fn/integrinβ1/FAK signalling‐dependent TGF‐β release from the ECM, thereby inducing gingival epithelial cell apoptosis via TGF‐βR/smad2 pathway.