Functional quantum dot-siRNA nanoplexes to regulate chondrogenic differentiation of mesenchymal stem cells.
SOX9 plays an important role in mesenchymal condensations during the early development of embryonic skeletons. However, its function in the chondrogenic differentiation of adult mesenchymal stem cells (MSCs) has not been fully investigated because SOX9 RNA interference in adult MSCs has seldom been studied. This study used SOX9 gene as the target gene and the quantum dot (QD)-based nanomaterial QD-NH2(ZnS shell and poly-ethylene glycol (PEG) coating) with a fluorescent tracer function as the gene carrier to transfect siSOX9 into MSCs after sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (sulfo-SMCC) activation in vitro and in vivo. The results showed that QD-SMCC could effectively bind and deliver siRNAs into the MSCs, followed by efficient siRNA escape from the endosomes. The siRNAs released from QD-SMCC retained their structural integrity and could effectively inhibit the targeted gene expression, leading to reduced chondrogenic differentiation of MSCs and delayed cartilage repair. QDs were excreted from living cells instead of dead cells, and the ZnS shell and PEG coating layer greatly reduced the cytotoxicity of the QDs. The transfection efficiency of QD-SMCC was superior to that of polyethylenimine (PEI). In addition, QD-SMCC has an intrinsic signal for noninvasive imaging of siRNA transport. The results indicate that SOX9 is imperative for the chondrogenesis of MSCs and QD-SMCC has great potential for real-time tracking of transfection.



In this study, we developed functional quantum dot (QD) nanoplexes by sulfosuccinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (sulfo-SMCC) activation of PEG-coated CdSe/ZnS QDs as the gene carrier of siRNA to study the effect of SOX9 RNA interference on the chondrogenic differentiation of MSCs. This study confirmed the importance of SOX9 in chondrogenesis, as evidenced by the findings that SOX9 knockdown significantly inhibited the expression of cartilage-specific markers including acan and col2a1 in MSCs and further delayed cartilage repair. Moreover, QD-SMCC has an intrinsic signal for noninvasive imaging of siRNA transport. The results indicate that SOX9 is imperative for the chondrogenesis of MSCs and QD-SMCC has great potential for real-time tracking of transfection.
Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China; Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Medical University, Nanning, China.
Yang
Y
Wu
Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Medical University, Nanning, China; Collaborative Innovation Center of Guangxi Biological Medicine, Guangxi Medical University, Nanning, China.
Bo
B
Zhou
Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Medical University, Nanning, China; Collaborative Innovation Center of Guangxi Biological Medicine, Guangxi Medical University, Nanning, China.
Fuben
F
Xu
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen, China.
Xiaoyong
X
Wang
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen, China.
Gang
G
Liu
Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Medical University, Nanning, China; Collaborative Innovation Center of Guangxi Biological Medicine, Guangxi Medical University, Nanning, China; The Medical and Scientific Research Center, Guangxi Medical University, Nanning, China. Electronic address: zhengli224@163.com.
Li
L
Zheng
Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China; Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Medical University, Nanning, China; The Medical and Scientific Research Center, Guangxi Medical University, Nanning, China; Guangxi Key Laboratory of Regenerative Medicine, Guangxi Medical University, Nanning, China. Electronic address: zhaojinmin@126.com.
Jinmin
J
Zhao
Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Medical University, Nanning, China; Collaborative Innovation Center of Guangxi Biological Medicine, Guangxi Medical University, Nanning, China; National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, China.
Xingdong
X
Zhang
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D002104:Cadmium / Q000032:analysis; D002356:Cartilage / Q000378:metabolism; D002454:Cell Differentiation; D002470:Cell Survival; D020219:Chondrogenesis; D000067493:Dynamic Light Scattering; D020868:Gene Silencing; D008301:Maleimides / Q000737:chemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009928:Organ Specificity; D045663:Quantum Dots / Q000378:metabolism* / Q000648:ultrastructure; D034741:RNA, Small Interfering / Q000378:metabolism*; D051381:Rats; D055758:SOX9 Transcription Factor / Q000378:metabolism; D012643:Selenium / Q000032:analysis; D013054:Spectrophotometry, Atomic; D055672:Static Electricity; D014162:Transfection
D015415:Biomarkers; D008301:Maleimides; D034741:RNA, Small Interfering; D055758:SOX9 Transcription Factor; C071675:sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate; D002104:Cadmium; D012643:Selenium
Chondrogenesis; Mesenchymal stem cell; Quantum dot; RNA interference