The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Periodontology, Cell Therapy Institute, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA.
Bone. 2018 Sep;114:40-49. doi: 10.1016/j.bone.2018.06.003. Epub 2018 Jun 5.
Osteoporosis is a serious health problem worldwide. Semaphorins (Sema) have been described as key molecules involved in the cross-talk between bone cells (osteoblasts/osteoclasts). In this study, we investigated whether plasmid containing Sema3a could ameliorate bone loss in an ovariectomized (OVX) mouse model via (AspSerSer), a selectively bone-targeting moiety. Plasmid pcDNA3.1(+)-Sema3a-GFP was fabricated and transfected cells with the plasmid demonstrated statistically higher levels of Sema3A in vitro (p < 0.001). Mice were ovariectomized and injected twice weekly with (AspSerSer)-(STR-R8)+pcDNA3.1(+)-Sema3a-GFP for four weeks. The aim of the study was twofold: firstly to design an effective bone-targeting drug-delivery system (AspSerSer). Secondly, the effects of Sem3A gene therapy on bone loss was investigated. Here, the targeting selectivity of pcDNA3.1(+)-Sema3a-GFP via (AspSerSer) to the trabecular bone surface was firstly verified by histological observation of frozen sections and immunofluorescence staining. Then, bone microstructure analysis by Micro-CT indicated significantly less bone loss in mice treated with (AspSerSer)-(STR-R8)+pcDNA3.1(+)-Sema3a-GFP compared to the control group (p < 0.05). Furthermore,H&E staining and Safranin O staining of the decalcified sections demonstrated statistically significantly higher bone area/total area in the mice that were injected with (AspSerSer)-(STR-R8)+pcDNA3.1(+)-Sema3a-GFP (p < 0.001, p < 0.01,respectively). TRAP staining and immunohistochemistry staining of COL I demonstrated lower numbers of osteoclasts and significantly increased numbers of osteoblasts in the bone-targeting moiety delivering pcDNA3.1(+)-Sema3a-GFP group, when compared to the control group (p < 0.01, p < 0.001,respectively). Together, our findings have identified that, (AspSerSer), a bone-targeting drug-delivery system based on semaphorin3A gene therapy, ameliorated bone loss in osteoporotic ovariectomized mice, by suppressing osteoclastic bone resorption and simultaneously increasing osteoblastic bone formation. Gene therapy by local site-specific Sema3A overexpression might be a potential new strategy for treating osteoporosis and bone defects.
骨质疏松症是一个全球性的严重健康问题。信号素（Sema）已被描述为参与骨细胞（成骨细胞/破骨细胞）之间串扰的关键分子。在这项研究中，我们通过（AspSerSer）研究了含有 Sema3a 的质粒是否可以改善去卵巢（OVX）小鼠模型中的骨丢失，（AspSerSer）是一种选择性的骨靶向部分。构建了质粒 pcDNA3.1(+)-Sema3a-GFP，并转染了该质粒的细胞在体外显示出统计学上更高水平的 Sema3A（p<0.001）。将小鼠去卵巢并每周两次注射（AspSerSer）-（STR-R8）+pcDNA3.1(+)-Sema3a-GFP 四周。该研究的目的有两个：首先，设计一种有效的骨靶向药物递送系统（AspSerSer）。其次，研究 Sem3A 基因治疗对骨丢失的影响。在这里，通过冷冻切片的组织学观察和免疫荧光染色首先验证了 pcDNA3.1(+)-Sema3a-GFP 通过（AspSerSer）对小梁骨表面的靶向选择性。然后，通过 Micro-CT 进行骨微结构分析表明，与对照组相比，用（AspSerSer）-（STR-R8）+pcDNA3.1(+)-Sema3a-GFP 治疗的小鼠骨丢失明显减少（p<0.05）。此外，脱钙切片的 H&E 染色和番红 O 染色表明，注射（AspSerSer）-（STR-R8）+pcDNA3.1(+)-Sema3a-GFP 的小鼠的骨面积/总面积显著增加（p<0.001，p<0.01，分别）。TRAP 染色和 COL I 的免疫组化染色表明，与对照组相比，骨靶向部分递送 pcDNA3.1(+)-Sema3a-GFP 的小鼠中的破骨细胞数量减少，成骨细胞数量显著增加（p<0.01，p<0.001，分别）。总之，我们的研究结果表明，基于信号素 3A 基因治疗的骨靶向药物递送系统（AspSerSer）通过抑制破骨细胞骨吸收和同时增加成骨细胞骨形成来改善去卵巢骨质疏松症小鼠的骨丢失。局部特异性 Sema3A 过表达的基因治疗可能是治疗骨质疏松症和骨缺损的一种有前途的新策略。
