Department of Endodontics, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, People's Republic of China.
Department of Orthodontics, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, People's Republic of China.
Int J Nanomedicine. 2024 Oct 4;19:10107-10128. doi: 10.2147/IJN.S480979. eCollection 2024.
In bone tissue engineering (BTE), cell-laden scaffolds offer a promising strategy for repairing bone defects, particularly when host cell regeneration is insufficient due to age or disease. Exogenous stem cell-based BTE requires bioactive factors to activate these cells. Graphene oxide quantum dots (GOQDs), zero-dimensional derivatives of graphene oxide, have emerged as potential osteogenic nanomedicines. However, constructing biological scaffolds with GOQDs and elucidating their biological mechanisms remain critical challenges.
We utilized GOQDs with a particle size of 10 nm, characterized by a surface rich in C-O-H and C-O-C functional groups. We developed a gelatin methacryloyl (GelMA) hydrogel incorporated with GOQDs-treated dental pulp stem cells (DPSCs). These constructs were transplanted into rat calvarial bone defects to estimate the effectiveness of GOQDs-induced DPSCs in repairing bone defects while also investigating the molecular mechanism underlying GOQDs-induced osteogenesis in DPSCs.
GOQDs at 5 μg/mL significantly enhanced the osteogenic differentiation of DPSCs without toxicity. The GOQDs-induced DPSCs showed active osteogenic potential in three-dimensional cell culture system. In vivo, transplantation of GOQDs-preactivated DPSCs/GelMA composite effectively facilitated calvarial bone regeneration. Mechanistically, GOQDs stimulated mitophagy flux through the phosphatase-and-tensin homolog-induced putative kinase 1 (PINK1)/Parkin E3 ubiquitin ligase (PRKN) pathway. Notably, inhibiting mitophagy with cyclosporin A prevented the osteogenic activity of GOQDs.
This research presents a well-designed bionic GOQDs/DPSCs/GelMA composite scaffold and demonstrated its ability to promote bone regeneration by enhancing mitophagy. These findings highlight the significant potential of this composite for application in BTE and underscore the crucial role of mitophagy in promoting the osteogenic differentiation of GOQDs-induced stem cells.
在骨组织工程（BTE）中，细胞负载支架为修复骨缺损提供了一种很有前途的策略，特别是当由于年龄或疾病导致宿主细胞再生不足时。基于外源性干细胞的 BTE 需要生物活性因子来激活这些细胞。氧化石墨烯量子点（GOQDs），是氧化石墨烯的零维衍生物，已成为有潜力的成骨纳米药物。然而，构建具有 GOQDs 的生物支架并阐明其生物学机制仍然是关键挑战。
我们使用了粒径为 10nm 的 GOQDs，其表面富含 C-O-H 和 C-O-C 官能团。我们开发了一种含有 GOQDs 处理的牙髓干细胞（DPSCs）的明胶甲基丙烯酰（GelMA）水凝胶。这些构建体被移植到大鼠颅骨骨缺损中，以评估 GOQDs 诱导的 DPSCs 在修复骨缺损方面的有效性，同时研究 GOQDs 诱导 DPSCs 成骨的分子机制。
GOQDs 在 5μg/ml 时可显著增强 DPSCs 的成骨分化，且无毒性。GOQDs 诱导的 DPSCs 在三维细胞培养系统中表现出活跃的成骨潜能。体内实验中，GOQDs 预激活的 DPSCs/GelMA 复合材料的移植有效促进了颅骨骨再生。在机制上，GOQDs 通过磷酸酶和张力蛋白同源物诱导的假定激酶 1（PINK1）/Parkin E3 泛素连接酶（PRKN）途径刺激线粒体自噬通量。值得注意的是，用环孢素 A 抑制线粒体自噬会阻止 GOQDs 的成骨活性。
本研究提出了一种设计良好的仿生 GOQDs/DPSCs/GelMA 复合支架，并证明其通过增强线粒体自噬来促进骨再生的能力。这些发现突出了该复合材料在 BTE 中应用的巨大潜力，并强调了线粒体自噬在促进 GOQDs 诱导的干细胞成骨分化中的关键作用。
