GROWTH DIFFERENTIATION FACTOR-5 STIMULATES THE GROWTH AND ANABOLIC METABOLISM OF ARTICULAR CHONDROCYTES

Objective To observe the effect of growth differentiation factor-5 (GDF-5) on the growth and anabolic metabolism of articular chondrocytes. Methods The articular chondrocytes isolated from rats were treated with various concentrations of rmGDF-5, and the growth of chondrocytes measured by MTT assay, the cellular cartilage matrices formation detected sulfated glycosaminoglycan by Alcian blue staining and type Ⅱcollagen by RT-PCR. Results After 7 days culture, MTT assay showed that GDF-5 enhanced the growth of chondrocytes in a dose-dependent manner, RT-PCR showed that GDF-5 clearly induced the synthesis of type Ⅱ collagen because of the col2a1 mRNA band more and more strong in a dose-dependent. Chondrocytes were cultured with GDF-5 for 14 days, the intensity of Alcian blue staining was greatly enhanced, especially, at a high concentration of 1000ng/mL, and GDF-5 enhanced the accumulation of the Alcian blue-stainable material in a concentration-dependent manner and in a does-dependent manner. Conclusion GDF-5 enhanced the growth of mature articular chondrocytes, and stimulated the cellular cartilage matrices formation in mono-layer culture.

Cloning of Integral Mature Peptide Gene of Human GDF-5

Summary: The integral mature peptide gene of human growth differentiation factor-5 (GDF-5) was cloned to provide the essential foundation for study on the biological characteristics of GDF-5 at gene and protein levels. Two primers were chemosynthesized according to the hGDF-5 sequence reported in Genbank. The hGDF-5 gene was gained by RT-PCR methods from the total RNA extracted from human fetus cartilage tissue, and was cloned into vector pMD18-T. The sequence of recombinant plasmid pMD18-T-hGDF-5 was analyzed by sequence analysis. DNA agarose gel electrophoresis showed that the product of RT-PCR was about 380bp, and double enzyme digestion of the recombinant plasmid corresponded with it. The result of sequence assay was in agreement with the reported hGDF-5 sequence in Genbank. Our results showed that the integral mature peptide gene of human GDF-5 was cloned successfully from human fetal cartilage tissue, and totally identified with the sequence of human GDF-5 in Genbank.

生长分化因子5诱导脂肪干细胞向成软骨细胞方向分化的实验研究

目的通过质粒转染探讨生长分化因子5(GDF-5)诱导大鼠脂肪干细胞向成软骨细胞方向分化的影响。方法选取雄性SD大鼠采用酶消化-密度梯度离心法提取脂肪干细胞行体外培养,并通过流式细胞术鉴定脂肪干细胞。体外培养的脂肪干细胞分3组,即转染组、空质粒组和对照组。转染组采用Lipofectamine^(TM)2000进行脂质体pcDNA3.1(+)/GDF-5重组质粒瞬间转染;空质粒组采用空质粒pcDNA3.1(+);对照组只加入等量脂质体。转染后观察各组细胞形态。同时,通过免疫组织化学、免疫荧光检测培养2周后Ⅱ型胶原表达水平,通过甲苯胺蓝染色检测2周后蛋白聚糖表达水平。结果转染2周后,空质粒组、对照组细胞形态未见明显变化,转染组长梭形的细胞明显向成软骨的多角形方向变化。Ⅱ型胶原经免疫组织化学染色,转染组可见棕黄色染色,空质粒组、对照组无明显染色;免疫荧光结果显示,转染组细胞呈亮绿色,空质粒组、对照组均未见明显染性着色。蛋白聚糖经甲苯胺蓝染色后转染组细胞呈蓝染,空质粒组、对照组均未见明显染性着色。结论pcDNA3.1(+)/GDF-5转染脂肪干细胞能显著增加Ⅱ型胶原、蛋白聚糖的表达,促进脂肪干细胞向成软骨细胞方向分化。

生长分化因子5基因真核表达质粒pcDNA3.1(+)/hGDF5的构建、鉴定及其活性检测

目的构建生长分化因子5(growth/differentiation factor 5,GDF5)基因的真核表达质粒pc DNA3.1(+)/h GDF5,并对其进行鉴定和活性检测。方法根据Genbank中人GDF5序列设计并合成引物,以p CA350-h GDF5质粒为模板进行聚合酶链式反应(polymerase chain reaction,PCR)扩增获得GDF5基因,并与pc DNA3.1(+)质粒连接构建真核表达质粒pc DNA3.1(+)/h GDF5。pc DNA3.1(+)/h GDF5经限制性内切酶消化、PCR扩增进行鉴定。将pc DNA3.1(+)/h GDF5分别转染MC615细胞及293细胞,利用PCR、Western blotting及免疫荧光法检测GDF5 m RNA及蛋白的表达。结果真核表达质粒pc DNA3.1(+)/h GDF5经限制性内切酶酶切、PCR扩增表明构建成功,PCR、Western blotting及免疫荧光实验结果显示真核表达质粒pc DNA3.1(+)/h GDF5能在MC615细胞及293细胞中稳定表达。结论成功构建了真核表达质粒pc DNA3.1(+)/h GDF5,为进一步研究GDF5的功能奠定了基础。

GDF5基因启动子表达载体的构建

目的构建含人生长分化因子5(GDF5)基因启动子表达载体pGL3-GDF5,为研究GDF5在骨骼、肌肉发育的作用机制提供实验基础。方法扩增人GDF5基因启动子序列,克隆至pGL3-Basic表达载体并转化入大肠杆菌DH10b,双酶切鉴定并测序。结果 PCR扩增后的产物在约854 bp处出现明显的特异性条带,酶切鉴定结果与理论预测值一致,测序未出现碱基突变。结论成功构建了含GDF5基因启动子的表达载体。

Effect of the gap junction blocker 1-heptanol on chondrogenic differentiation of mouse bone marrow mesenchymal stem cells in vitro

Objective：To investigate the effect of the gap junction blocker 1-heptanol on the in vitro chondrogenic differentiation of mouse bone marrow mesenchymal stem cells（MSCs） following induction by GDF-5. Methods：MSCs were isolated from mouse bone marrow and cultured in vitro. After 3 passages cells were induced to undergo chondrogenic differentiation with recombinant human GDF-5（100 ng/ml）, with or without 1-heptanol（2.5 la mol/L）. The effect of 1-heptanol on MSCs proliferation was investigated using the MTT assay. Type II collagen mRNA and protein were examined by RT-PCR and immunocytochemistry respectively, and the sulfate glycosaminoglycan was assessed by Alcian blue dye staining. Connexin43（Cx43） protein was examined by western blotting. Results：GDF-5 induced proliferation and chondrogenic differentiation of MSCs. While 1-heptanol treatment had no effect on this proliferation, it inhibited the expression of both type II collagen mRNA and protein. The Alcian blue staining revealed that 1-heptanol also inhibited the deposition of the typical cartilage extracellular matrix promoted by recombinant GDF-5. Western blotting demonstrated that 1-heptanol had no effect on the expression of Cx43. Conclusion：These results suggest that mouse bone marrow MSCs can be differentiated into a chondrogenic phenotype by GDF- 5 administration in vitro. While the gap junction blocker, 1-heptanol, did not reduce gap junction Cx43, these intercellular communication pathways clearly played an important functional role in GDF-5-induced cartilage differentiation.

携载生长分化因子5质粒的壳聚糖-透明质酸-硫酸软骨素微球在骨关节炎基因治疗中的应用（英文）

目的:骨关节炎是临床上的一种常见病和多发病。本研究尝试利用壳聚糖、透明质酸和硫酸软骨素为载体,制备一种携载生长分化因子5(GDF-5)质粒的纳米微球用于骨关节炎的基因治疗。创新点:首次利用壳聚糖、透明质酸、硫酸软骨素三种原料制备可携载GDF-5质粒的三元纳米微球,并将其应用到骨关节炎的治疗中。方法:在55°C下,按不同比例混合壳聚糖、透明质酸钠、硫酸软骨素和GDF-5质粒,利用静电吸附原理制备携载GDF-5质粒的三元纳米微球。分别利用扫描电镜和激光粒度散射仪测试微球的形貌和粒径;利用凝胶电泳检测质粒与微球的结合情况;利用CCK-8检测微球的细胞毒性。将携载GDF-5质粒的微球与软骨细胞共培养,并将脂质体和空载组作为对照组,在预定的时间点通过免疫荧光染色、免疫组化染色以及生化成分分析,观察微球对软骨细胞外基质分泌情况的影响。最后将该纳米微球注射到骨关节炎模型兔体内,通过大体观察、苏木精-伊红(H&E)染色、免疫荧光染色和免疫组化分析该微球对骨关节炎的作用。结论:本研究成功地利用壳聚糖、透明质酸和硫酸软骨素为原料,制备出携载GDF-5质粒的纳米微球。其中GDF-5质粒可以有效地促进软骨细胞外基质的分泌,透明质酸和硫酸软骨素是临床上常见的治疗骨关节炎的药物。微球具有良好的理化性能,其细胞毒性小,转染效率高,在体内外均能有效地促进软骨细胞外基质的分泌,能够在一定程度上延缓骨关节炎的进展。该纳米微球将是一种极具希望的可应用于骨关节炎基因治疗的载体。