鼠骨髓基质干细胞的特性及向成骨细胞的分化

目的分离纯化成年小鼠骨髓基质干细胞并进行定向诱导。方法利用Percoll液分离成年小鼠骨髓基质干细胞,Ter119、CD45磁珠纯化细胞,培养2-3代的细胞用矿化液进行定向诱导。对诱导前后的细胞进行免疫组化染色。结果 镜下见原代细胞呈多种形态。Ter119、CD45磁珠筛选可获得纯度达57.95％以上骨髓基质干细胞。碱性磷酸酶、Von Kossa染色阳性,油红染色弱阳性,矿化液诱导2周后,可形成钙结节。结论利用Percoll液结合磁珠分离法是离体条件下获得骨髓基质干细胞的一个简便有效的方法,纯化后定向诱导可得到较纯的成骨细胞。     

周期性牵张应变对大鼠骨髓间充质干细胞神经向分化的影响

目的 研究周期性牵张应变对大鼠骨髓间充质干细胞(rat bone marrow-derived mesenchymal stem cells, rBMSCs)向神经细胞分化的影响。方法 对rBMSCs加载不同幅度周期性应变24 h,然后继续培养5 d,检测神经细胞标志物表达和相关信号通路蛋白磷酸化水平。通过有限元分析牵张作用下细胞表面的应力分布。通过转录组测序分析周期性牵张应变引起差异表达的基因。结果 5%幅度、0.5 Hz周期性牵张应变可以显著促进神经细胞标志物的表达,提高细胞内胞外信号调节激酶(extracellular-signal-regulated kinase, ERK)、蛋白激酶B (AKT)和哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin, mTOR)的磷酸化水平。KEGG通路富集分析发现,与细胞黏附、细胞外基质和受体相互作用相关的基因在周期性牵张作用后显著提高。结论 周期性牵张应变可以改变细胞与细胞外基质的相互作用,激活AKT/mTOR和ERK信号通路,从而促进rBMSCs向神经细胞分化。了解力学刺激对间充质干细胞分化的影响有望提高...     

Effect of Focal Adhesion Kinase on the Regulation of Realignment and Tenogenic Differentiation of Human Mesenchymal Stem Cells by Mechanical Stretch

Focal adhesion kinase (FAK) is a focal adhesion-associated protein kinase involved in cell adhesion and spreading. It is recruited as a participant in focal adhesion dynamics between cells and has a role in cell motility, differentiation, and survival. The role of FAK in the differentiation of human mesenchymal stem cells (hMSCs), however, is not well understood, particularly in terms of tenogenic differentiation. In this study, we reported that FAK regulates the mechanical stretch-induced realignment of hMSCs. We showed that FAK can be activated by mechanical stretch and, with a 10 μM PF 573228 (a novel small molecule inhibitor of FAK) treatment, FAK autophosphorylation at Tyr397 is significantly decreased. Moreover, our findings demonstrated that this decrease in FAK autophosphorylation at Tyr397 leads to the attenuation of upregulation of mechanical stretch-induced mRNA expression of tendon-related genes, including type I collagen, type III collagen, tenascin-C, and scleraxis. These results indicate that the FAK signaling molecule plays an important role in regulating cell realignment and tenogenic differentiation of hMSCs when induced by mechanical stretch. Collectively, our findings provide novel insight into the role of FAK in the realignment and mechanotransduction of hMSCs during the process of tenogenic differentiation induced by mechanical stretch.     

BMP4/Smad Signaling Pathway Induces the Differentiation of Mouse Spermatogonial Stem Cells via Upregulation of Sohlh2

Spermatogonial stem cells (SSCs) capable of self‐renewal and differentiation are the foundation for spermatogenesis. Although several factors that govern these processes have been investigated, the underlying molecular mechanisms have not been fully elucidated. Here, we investigated the role of BMP4 in mouse SSC differentiation, and found that SSCs cultured in the presence of BMP4 underwent differentiation, characterized by downregulation of SSC self‐renewal markers, Plzf, and upregulation of SSC differentiation marker, c‐kit. Smad1/5/8 proteins were phosphorylated during BMP4‐induced differentiation. The effects of BMP4 on SSCs were blocked by BMP4 inhibitor (Dorsomorphin). The activation of BMP4/Smad signaling pathway in SSCs increased the expression of Sohlh2, which is involved in the early differentiation of spermatogonia. Knockdown sohlh2 expression by RNA interference abolished the effect of BMP4 on SSC differentiation and the upregulation of c‐kit expression. Overall, our results suggest that BMP4 plays an important role during the early differentiation of SSCs via upregulation of sohlh2. Anat Rec, 297:749–757, 2014. © 2014 Wiley Periodicals, Inc.     

力学刺激诱导骨髓间充质干细胞选择分化的研究进展

机体细胞／组织处于复杂的力学环境中，力学刺激对细胞的形态、发育和功能起着重要的调节作用。骨髓间充质干细胞的增殖、选择分化受多种力学因素的影响，而且力学刺激的大小、方式以及作用时间对骨髓间充质干细胞定向分化的调节作用不尽相同。作者就力学因素对骨髓间充质干细胞选择分化的调节作用进行简要的综述。     

bFGF纳米控释载体对骨髓间充质干细胞的生物学作用

本研究旨在探讨甲基丙烯酸缩水甘油酯右旋糖酐(dex-GMA)载碱性成纤维细胞生长因子(bFGF)凝胶纳米微球(dex-GMA-bFGF-NPs)对骨髓间充质干细胞(BMSCs)生物学作用。采用改良乳液聚合技术合成纳米微球,将单纯bFGF(A组)、空白dex-GMA凝胶纳米微球(B组)和载bFGF凝胶纳米微球(C组)加入骨髓间充质干细胞培养液中,不添加任何添加物的单纯MSCs为空白对照组(D),用细胞计数法、噻唑蓝比色法(MTT法)、流式细胞术观察细胞增殖情况;并检测细胞ALP活性,以反映dex-GMA-bFGF-NPs对BMSCs分化情况的影响。结果显示:dex-GMA-bFGF-NPs大小均匀,包封率高达88%,85%的bFGF在前14 d释放。dex-GMA-bFGF-NPs对bFGF缓释有效促进BMSCs的增殖,在培养12 d后,A、B、C和D组细胞数分别为(21.97±0.25)×104个细胞/ml(、12.43±0.13)×104个细胞/ml(、27.45±0.78)×104个细胞/ml和(12.03±0.43)×104个细胞/ml,差异有统计学意义(P0.05),培养3 d后,A组的G2/M+S期百分数最高,7 d后,C组的G2/M+S期百分数最高。结论:dex-GMA-bFGF-NPs可控制活性bFGF的长时间持续释放,作为bFGF的缓释载体,可明显促进骨髓间充质干细胞的增殖和分化。     

低氧预适应小鼠脑内ERK1/2磷酸化水平和蛋白表达量的改变

目的：初步探讨细胞外信号调节激酶（Extraeellular signal-regulated kinases，ERK1／2）在脑低氧预适应发生发展过程中的作用。方法：按已建小鼠整体低氧预适应模型，将BALB／C小鼠（18-22g，雌雄不限）随机分为正常对照（H0）、早期（H1-H4）和延迟性（U5-H6）低氧预适应等7组（每组至少6只动物）。应用SDS-PAGE和Western blot等生化技术，并结合Gel Doc凝胶成像系统，半定量检测小鼠脑组织内ERK1／2的磷酸化水平和蛋白表达量。结果：①早期低氧预适应形成过程中，随低氧暴露次数的增加（H1-H4），小鼠海马和皮层组织内ERK1／2磷酸化水平显著降低（P〈0．05，n=6），而ERK1／2蛋白表达量并无显著变化；②延迟性低氧预适应中（H5-H6），小鼠大脑皮层和海马组织内ERK1／2的蛋白表达量显著降低（P〈0．05，n=6）。结论：ERK1／2的活性降低（磷酸化水平降低），以及ERK1／2蛋白表达量下调可能分别参与了脑早期低氧预适应和晚期延迟性低氧预适应的发生发展过程。     

骨桥蛋白对骨髓间充质干细胞核力学特性的影响及相关分子机制

目的研究骨桥蛋白(osteopontin,OPN)对骨髓间充质干细胞(bone marrow-derived mesenchymal stem cells,BMSCs)核力学特性的影响及相关分子机制。方法采用Transwell法分析BMSCs迁移能力。利用原子力显微镜(atomic force microscope,AFM)检测细胞核弹性模量,分析OPN作用下BMSCs细胞核硬度的变化。通过Western blot技术检测OPN作用对黏着斑激酶(focal adhesion kinase,FAK)和胞外信号调节激酶1/2(extracellular signal-regulated kinase 1/2,ERK 1/2)的影响,并利用FAK或ERK1/2抑制剂考察FAK-ERK1/2信号通路在OPN影响BMSCs核力学特性中的作用。通过RT-PCR和Western blot技术检测OPN作用下核纤层蛋白Lamin A/C的表达变化。结果 OPN处理组细胞核弹性模量与对照组相比明显降低。OPN作用显著上调FAK、ERK1/2磷酸化水平,加入FAK或ERK1/2抑制剂在一定程度上回救OPN降低的细胞核弹性模量,并显著抑制BMSCs迁移。OPN处理BMSCs后Lamin A/C mRNA和蛋白水平的表达出现下调,但FAK或ERK1/2抑制剂能够抑制OPN诱导的Lamin A/C表达下调。结论 OPN可能通过FAK-ERK1/2信号通路下调BMSCs核骨架蛋白Lamin A/C表达,降低细胞核硬度,促进BMSCs迁移。该研究结果为深入认识OPN调控BMSCs迁移行为的机制及其临床应用提供了实验依据。     

葛根素通过ERK1/2信号通路促进内皮细胞增殖

目的:体外观察葛根素对人脐静脉内皮细胞(HUVEC)的促增殖作用,并对其机制进行初步探讨。方法:采用四甲基偶氮唑蓝(MTT)法检测不同浓度葛根素对HUVEC细胞增殖的影响;流式细胞术检测细胞凋亡;Western blot检测p-ERK1/2蛋白表达水平。结果:葛根素能剂量依赖性促进HUVEC增殖,在80μM效果最明显,且作用36h时,能显著减少早期凋亡,激活ERK1/2磷酸化。结论:葛根素素对人脐静脉内皮细胞有明显的促进增殖作用,其作用可能与ERK1/2的活化有关。     

氯沙坦通过ERK1/2 MAPK途径抑制高糖诱导小鼠系膜细胞CTGF表达

目的: 研究高糖环境下, 氯沙坦对CTGF的影响以及其作用机制.方法: 体外培养小鼠系膜细胞株(MMCs), 用高糖(25 mmol/L葡萄糖)刺激细胞分别作用24 h、 48 h、 72 h, 用Western blot方法检测磷酸化ERK1/2的表达.再将细胞分为低糖组(5.6 mmol/L葡萄糖), 山梨醇组(5.6 mmol/L葡萄糖+19.4 mmol/L山梨醇), 高糖组(25 mmol/L葡萄糖), 氯沙坦组(25 mmol/L葡萄糖+10-5 mol/L氯沙坦)以及 ERK抑制剂组(25 mmol/L葡萄糖+ 25 μmol/L PD98059), 48 h后采用Western blot方法检测磷酸化ERK1/2的表达, 72 h后采用Real-time PCR方法及Western blot分别检测 CTGF mRNA表达量以及蛋白的表达.结果: 高糖刺激小鼠系膜细胞后, ERK1/2磷酸化的蛋白表达逐渐增高, 呈现一定时间依赖性.与低糖组相比, 高糖组磷酸化ERK1/2、 CTGF的蛋白表达明显增加(P<0.01), 而与高糖组相比, 氯沙坦组以及ERK抑制剂组磷酸化ERK1/2的蛋白表达以及CTGF的蛋白均明显下降有统计学意义(P<0.05).与低糖组相比, 高糖组CTGF mRNA表达量明显增加(P<0.01), 而与高糖组相比, 氯沙坦组以及ERK抑制剂组CTGF mRNA表达量明显下降, 且有统计学意义(P<0.01).结论: 氯沙坦可抑制高糖对CTGF的诱导作用, 其机制可能与抑制ERK1/2 MAPK途径有关.     

Edaravone对大鼠弥漫性脑创伤后ERK1/2通路的影响

为探讨Edaravone对脑创伤的保护机制,本研究观察了Edaravone对弥漫性脑创伤大鼠脑组织磷酸化细胞外信号调节激酶ERK1/2表达变化的影响。114只雄性SD大鼠,随机分为3组:(1)假手术对照组(A组,n=18),(2)创伤组(B组,n=48),(3)Edaravone治疗组(C组,n=48),采用Marmarou’s法建立大鼠弥漫性颅脑损伤模型。伤后1、3、6、24、48和72h,HE染色观察伤后皮质和海马区神经细胞组织形态变化,Western blot法、免疫组化法检测皮质和海马区p-ERK1/2的表达,术后24、48、72h对大鼠神经运动功能和综合运动能力评分。结果显示:光镜下,伤后6、24h即可见B组大脑皮质和海马区神经细胞胞体收缩呈三角形,胞浆嗜色性减弱,核皱缩浓染,细胞周围出现空隙,即神经细胞变性坏死改变,C组上述改变明显减轻;免疫组化与Western blot法结果显示,与A组比较,B组ERK1/2(即p-ERK1/2)活性在伤后1、3、6、24、48h显著增高(P<0.05);与B组比较,C组中p-ERK1/2在6、24及48h显著回降(P<0.05);神经功能与综合运动能力评分在B组中(8.73±1.4,63.8±27.7)明显低于A组(24.00±0.00,278.4±27.7),C组(17.36±1.63,117.6±20.9)显著回升(P<0.05)。本研究表明Edaravone可改善脑创伤后神经功能损伤,其机制与调节脑创伤后ERK1/2信号活化水平有关。     

Adipophilin通过ERK1/2-AP-1途径诱导炎症因子的表达

目的:观察巨噬细胞中脂肪分化相关蛋白(adipophilin)对炎症因子表达的影响,阐明adipophilin促进巨噬细胞炎症因子表达的机制。方法:将已构建成功的adipophilin稳定高、低表达逆转录病毒载体转染入PA317包装细胞,制备adipophilin高和低表达的RAW264.7细胞;收集已转染成功的各组细胞上清液,用ELISA方法检测IL-6、TNF-α、MCP-1等炎症因子在细胞培养液中的浓度。Western blot检测各组细胞AP-1、p-AP-1、ERK1/2及p-ERK1/2的蛋白水平;用ERK1/2抑制剂PD98059或AP-1抑制剂curcumin孵育细胞,检测各组细胞中以上指标的变化情况。结果:高表达adipophilin的细胞上清液中炎症因子IL-6、MCP-1和TNF-α浓度明显增高,adipophilin siRNA组细胞中的炎症因子降低;高表达adipophilin的细胞中p-ERK1/2和p-AP-1的蛋白水平增高,adipophilin siRNA组则减少;ERK1/2抑制剂PD98059使AP-1蛋白活性明显下调;给予AP-1抑制剂curcumin后,细胞培养液中的IL-6、MCP-1和TNF-α浓度明显下降。结论:Adipophilin在RAW264.7巨噬细胞中能够促进炎症因子的表达。     

吡格列酮上调ERK1/2与Bcl-2在心肌细胞缺血再灌注损伤大鼠心肌细胞的表达

目的研究吡格列酮对ERK1/2与Bcl-2信号转导通路在大鼠心肌缺血再灌注损伤中的作用。方法取半日龄到一日龄Wistar大鼠幼鼠心室肌细胞进行体外培养,并建立缺血再灌注模型。体外培养的细胞分为正常对照组(C组)、缺血再灌注组(I组)、缺血再灌注组+吡格列酮处理组(P组)和P组+ERK1/2抑制剂PD98059处理组(P+Pd组)。采用Western-bloting和免疫细胞化学染色法检测细胞内Bcl-2蛋白的含量。结果 Western-bloting与免疫细胞化学法显示,I组Bcl-2蛋白表达水平高于C组(0.05),P组的Bcl-2蛋白表达高于I组,P+Pd组Bcl-2蛋白表达水平低于P组(0.05)。结论吡格列酮对心肌细胞缺血再灌注损伤的保护可能与下调ERK1/2和Bcl-2转导通路有关。     

Co-culture with Endothelial Progenitor Cells promotes the Osteogenesis of Bone Mesenchymal Stem Cells via the VEGF-YAP axis in high-glucose environments

Patients with type 2 diabetes mellitus (T2DM) have a high risk of fracture and experience poor bone healing. In recent years, bone mesenchymal stem cells (BMSCs) and endothelial progenitor cells (EPCs) have become the most commonly used cells in cell therapy and tissue engineering. In this study, we found that high glucose levels had a negative effect on the differentiation of BMSCs and EPCs. Considering that EPCs-BMSCs sheets can provide endothelial cells and osteoblastic cells, we transplanted cell sheets into T2DM rats with bilateral skull defects. The outcomes of the in vivo study revealed that EPCs-BMSCs sheets promoted ossification, which was verified by micro-CT and immunohistochemistry (IHC) analyses. Furthermore, we detected the VEGF content in the culture supernatant using an enzyme-linked immunosorbent assay (ELISA). The results showed that the BMSCs co-cultured with EPCs presented a higher level of VEGF than other cells. To assess the differentiation and migration of BMSCs exposed to VEGF, ALP staining, scratch assay and qRT-PCR analysis were performed. In addition, we used immunofluorescence and western blotting analysis to further explore the related mechanisms. The results showed that cells cultured with VEGF had a stronger actin cytoskeleton and a greater amount of nuclear and total YAP than cells cultured without VEGF. Taken together, our results indicate that co-culture with EPCs could promote the osteogenesis of BMSCs partially via VEGF. Furthermore, YAP and F-actin play important roles in this process.     

Synergistic effects of snail and quercetin on renal cell carcinoma Caki-2 by altering AKT/mTOR/ERK1/2 signaling pathways

Renal cell carcinoma has become the most common subtype of kidney cancer, and has the highest propensity to manifest as metastatic disease. Because of lack of knowledge in events that correlated with tumor cell migration and invasion, few therapeutic options are available. Therefore, in current study, we explore the anti-tumoral effect of a potential chemopreventive natural product, quercetin, combined with anti-sense oligo gene therapy (inhibiting Snail gene). We found that either one of them had the remarkable effects in suppressing cell proliferation and migration, inducing cell cycle arrest and apoptosis in a ccRCC cell line, Caki-2 cells. The combination of both means provides even strong suppressive effects toward these ccRCC cells. Our study, for the first time, provides the possibility of using a novel treatment for renal cancer, by combining natural product and gene therapy.     

Bone Morphogenetic Protein-9 Induces Osteogenic Differentiation of Rat Dental Follicle Stem Cells in P38 and ERK1/2 MAPK Dependent Manner

Dental follicle stem cells are a group of cells possessing osteogenic, adipogenetic and neurogenic differentiations, but the specific mechanism underlying the multilineage differentiation remains still unclear. Great attention has been paid to bone morphogenetic protein-9 (BMP-9) due to its potent osteogenic activity. In the present study, rat dental follicle stem cells were isolated and purified, and cells of passage 3 underwent adenovirus mediated BMP-9 gene transfection to prepare dental follicle stem cells with stable BMP-9 expression. Detection of alkaline phosphatase (ALP) and calcium deposition showed dental follicle stem cells transfected with BMP-9 gene could significantly promote the osteogenesis. In addition, SB203580 and PD98059 were employed to block the p38 mitogen-activated protein kinase (p38MAPK) and extracellular signal-regulated kinase (ERK1/2), respectively. Detection of ALP and calcium deposition revealed the BMP-9 induced osteogenic differentiation of dental follicle stem cells depended on MAPK signaling pathway.