A pilot trial on the molecular pathophysiology of traumatic temporomandibular joint bony ankylosis in a sheep model. Part I: Expression of Wnt signaling

ObjectiveTo preliminarily investigate the temporal patterns of the endogenous mRNA expression for members of the Wnt signaling and a series of genes regulating bone formation during the development of traumatic temporomandibular joint (TMJ) bony ankylosis in a sheep model.MethodsSix sheep were used for the induction of bony ankylosis of TMJ. We performed a condylar fracture, excision of the lateral 2/3 disc and serious injury to the glenoid fossa to induce bony ankylosis on the right TMJ. An isolated condylar fracture was performed on the left side. Two sheep were sacrificed at 1 month, 3 months, and 6 months after surgery, respectively. The specimens from the ankylosed joint and the condylar fracture were harvested for RNA extraction respectively. In this report (Part I), only the bony ankylosed samples were used for analysis of gene expressions. The specimens 1 month postoperatively were taken as the control, and the changes of expression of target genes over time were examined by real-time PCR.ResultsmRNA expression of Wnt1, Wnt2b, Wnt3a, β-catenin, Sfrp1, Lrp6, Lef1, CyclinD1, and Runx2 was up-regulated at 3 and 6 months compared with 1 month. The expression of Wnt5a, Sox9, and Osterix was up-regulated with a peak at 3 months, and then fell back to the basal levels at 6 months. The expression of Ocn began to up-regulate until 6 month postoperatively.ConclusionOur findings suggested that Wnt signaling was involved in the formation of traumatic TMJ bony ankylosis and thus may be a potential therapeutic target for the treatment of the disease in the future.     

白藜芦醇预处理介导Wnt/β-catenin信号通路保护脑缺血再灌注大鼠海马区神经元损伤

目的:研究白藜芦醇(resveratrol,Res)预处理对脑缺血再灌注(ischemia reperfusion,I/R)大鼠海马区Wnt/β-catenin信号通路相关蛋白的表达量、星形胶质细胞及神经元形态的影响,探讨白藜芦醇对脑缺血再灌注大鼠海马区神经元损伤的保护作用机制。方法:将SD大鼠60只随机分为四组,每组15只:正常对照组(Control)、假手术组(Sham)、缺血再灌注组(I/R)和白藜芦醇治疗组(Res)。Res组大鼠连续7 d腹腔注射白藜芦醇(每日30 mg/kg,由2%DMSO溶解),Sham组和I/R组注射同等量2%DMSO;7 d后Res组和I/R组采用改良线栓法制备大鼠大脑中动脉阻塞(middle cerebral artery occlusion,MACO)模型,缺血90 min,再灌注24 h。Sham组仅分离暴露一侧颈内动脉,不插入线栓;24 h后对各组大鼠进行神经功能学评分;脑组织TTC染色;尼氏染色;免疫组化检测海马区GSK-3β和星型胶质细胞(GFAP)数量及形态变化;Western Blot分别检测Wnt信号通路相关因子GSK-3β、p-GSK-3β、β-catenin蛋白水平表达量。结果:再灌注24 h后,尼氏染色显示与I/R组相比Res组海马区仅有少量的神经元破碎和消失,形态尚完整(P0.05),同时行为学评分和梗死面积也低于I/R组(P0.05)。免疫组化显示,与I/R组相比Res组GSK-3β的表达量明显降低,伴随星形胶质细胞活化状态和数量减少(P0.05)。Western Blot显示,与免疫组化表达趋势结果一致Res组GSK-3β的的表达量明显低于I/R组,而p-GSK-3β、β-catenin的表达量均增高(P0.05)。结论:白藜芦醇可能是通过调节Wnt/β-catenin信号通路相关蛋白的表达进而有效的降低大鼠脑缺血再灌注后神经元的损伤。     

Wnt信号途径与常见皮肤肿瘤

Wnt信号途径的传导和调控在胚胎发育和细胞恶性转变中起着重要作用,对其深入的研究,会对肿瘤的发生发展机制产生新的理解和认识。根据近几年国内外相关文献,对Wnt信号途径在常见皮肤肿瘤的发病机制进行评价,对最新研究进展进行综述,可以为肿瘤的早期诊断以及治疗提供良好的分子标记。     

GSK-3β suppresses the proliferation of rat hepatic oval cells through modulating Wnt/β-catenin signaling pathway

Aim:

Glycogen synthase kinase 3β (GSK-3β) plays a crucial role in hepatic biology, including liver development, regeneration, proliferation and carcinogenesis. In this study we investigated the role of GSK-3β in regulation of growth of hepatic oval cells in vitro and in liver regeneration in partially hepatectomized rats.

Methods:

WB-F344 cells, the rat hepatic stem-like epithelial cells, were used as representative of oval cells. Cell viability was examined using a WST-8 assay. The cells were transfected with a recombinant lentivirus expressing siRNA against GSK-3β (GSK-3βRNAiLV) or a lentivirus that overexpressed GSK-3β (GC-GSK-3βLV). Adult rats underwent partial (70%) hepatectomy, and liver weight and femur length were measured at d 7 after the surgery. The expression of GSK-3β, phospho-Ser⁹-GSK-3β, β-catenin and cyclin D1 was examined with immunoblotting assays or immunohistochemistry.

Results:

Treatment of WB-F344 cells with the GSK-3β inhibitor SB216763 (5 and 10 μmol/L) dose-dependently increased the levels of phospho-Ser⁹-GSK-3β, but not the levels of total GSK-3β, and promoted the cell proliferation. Knockout of GSK-3β with GSK-3βRNAiLV increased the cell proliferation, whereas overexpression of GSK-3β with GC-GSK-3βLV decreased the proliferation. Both SB216763 and GSK-3βRNAiLV significantly increased the levels of β-catenin and cyclin D1 in the cells, whereas GSK-3β overexpression decreased their levels. In rats with a partial hepatectomy, administration of SB216763 (2 mg/kg, ip) significantly increased the number of oval cells, the levels of phospho-Ser⁹-GSK-3β, β-catenin and cyclin D1 in liver, as well as the ratio of liver weight to femur length at d 7 after the surgery.

Conclusion:

GSK-3β suppresses the proliferation of hepatic oval cells by modulating the Wnt/β-catenin signaling pathway.     

帕立骨化醇抑制糖尿病肾病大鼠肾小管间质纤维化

目的:探讨帕立骨化醇(paricalcitol,P)对糖尿病肾病(DN)肾小管间质纤维化的干预作用及可能机制。方法:大鼠禁食后,采用单次无菌腹腔注射链脲佐菌素建立DN模型。将DN大鼠随机分为:(1)帕立骨化醇干预组(P组):帕立骨化醇溶于丙二醇中,于造模成功后第2天以0.4μg/kg的剂量腹腔注射,每周3次;(2)糖尿病肾病组(D组):给予等体积的丙二醇腹腔注射。设置正常对照组(C组)。帕立骨化醇连续干预12周后,测血、尿生化指标;进行肾脏病理学检查;利用免疫组化及Western blotting检测肾组织TGF-β1、Wnt-4、β-catenin及Klotho蛋白的表达;并进行指标间的相关分析。结果:(1)与C组比较,D组大鼠SCr、BUN及24 h尿蛋白水平均升高,而P组均较D组降低(P0.05)。(2)与C组比较,D组大鼠肾小管间质纤维化面积增加,而P组较D组减小(P0.05)。(3)D组大鼠肾组织Klotho蛋白表达低于C组,而P组高于D组(P0.05);与C组比较,D组大鼠肾组织TGF-β1、Wnt-4及β-catenin蛋白表达增加,而P组表达均较D组减少(P0.05)。(4)Klotho与纤维化面积、TGF-β1、Wnt-4及β-catenin均呈负相关(P0.05)。结论:帕立骨化醇可抑制DN大鼠肾小管间质纤维化,其作用可能与增加肾组织Klotho表达,抑制Wnt/β-catenin信号通路激活,同时减少TGF-β1合成相关。     

阻断经典Wnt通路对棕色脂肪干细胞向起搏样细胞分化的作用

目的:研究阻断经典Wnt通路对棕色脂肪干细胞向起搏样细胞分化的影响。方法:在诱导棕色脂肪干细胞向起搏特性诱导的过程中,培养基中加入经典Wnt通路阻断剂Dkk-1培养10 d。相差显微镜观察诱导组细胞的形态学变化、应用real-time PCR检测其中起搏细胞发育相关结构基因的表达情况,免疫荧光显色普通光镜和激光共聚焦显微镜观察起搏特征分子的蛋白表达。结果:分化后的棕色脂肪干细胞具有起搏细胞特性,经Dkk-1诱导后,棕色脂肪干细胞向起搏样细胞的转化率明显提高,起搏细胞发育相关基因和蛋白表达明显上调。结论:阻断经典Wnt通路可促进棕色脂肪干细胞向起搏样细胞的分化。     

Wnt/β-catenin信号通路对孤独症模型大鼠重复呆板样行为的影响

目的　探讨Wnt/β-catenin信号通路对孤独症发生过程中重复呆板样行为的影响。 方法　利用丙戊酸（valproic acid,VPA）孤独症动物模型,检测了经典Wnt信号通路关键信号分子β-catenin及其负性调节因子GSK-3β在孤独症模型大鼠小脑脑区的表达变化;同时检测孤独症模型大鼠重复呆板样行为变化。Western blotting法检测GSK-3β、β-catenin总蛋白及磷酸化蛋白表达,运用旷场实验检测重复呆板样行为持续的时间、次数。 结果　与对照组相比,在小脑脑区模型组GSK-3β磷酸化蛋白表达增加,β-catenin磷酸化蛋白表达减少;重复呆板样行为持续的时间、次数均增加。 结论　孤独症大鼠小脑脑区经典wnt信号通路活性增加,运动亢进,提示经典Wnt信号通路活性增加可能导致重复呆板样行为变化,进而导致对孤独症的易感性增加。     

Wnt signaling in rheumatoid synoviocyte activation

Rheumatoid arthritis (RA) is a joint-specific disease with complex pathogenesis. It is characterized by synovial inflammation, cartilage loss, and joint destruction. The reasons why joint damage recurs when therapy is discontinued are not clearly understood. Several lines of evidence suggest that cartilage damage is promoted by the transformed and invasive fibroblast-like synoviocytes (FLS) of the rheumatoid joint. It has been demonstrated in several systems that aberrant wnt-mediated signaling causes blockade of cartilage differentiation and malformation of joints. In this review, we have discussed the importance of wnt–frizzled-mediated signaling in the autonomous activation of FLS in patients with RA. Anti-wnt/anti-frizzled antibodies, frizzled receptor antagonists, or small molecule inhibitors of wnt–frizzled signaling might be useful for therapeutic interventions in RA. Received: May 15, 2001/Accepted: September 28, 2001