Effects of areca nut consumption on cell differentiation of osteoblasts, myoblasts, and fibroblasts

Areca nut is used worldwide as a hallucinogenic addicting drug along the tropical belt.Arecoline,a toxic compound,is the most important alkaloid in areca nuts.The adverse effects of oral uptake and chewing of areca nut are well known.For example,the possibility of cancer caused by chewing areca nuts is widely discussed.Chewing areca nut has other adverse effects on other organs,including abnormal cell differentiation,oral cancer,and several other diseases.The use of areca nut is also associated with low birthweight.Skeletal musculature is the largest organ in the body and is attached to the bones.During embryo development,the differentiation of bone and muscle cells is critical.In this article,we reviewed the effects of areca nut and arecoline on embryonic cell differentiation,particularly osteoblasts,myoblasts,and fibroblasts.

miR-23a/b regulates the balance between osteoblast and adipocyte differentiation in bone marrow mesenchymal stem cells

Age-related osteoporosis is associated with the reduced capacity of bone marrow mesenchymal stem cells （BMSCs） to differentiate into osteoblasts instead of adipocytes. However, the molecular mechanisms that decide the fate of BMSCs remain unclear. In our study, microRNA-23a, and microRNA-23b （miR-23a/b） were found to be markedly downregulated in BMSCs of aged mice and humans. The overexpression of miR-23a/b in BMSCs promoted osteogenic differentiation, whereas the inhibition of miR-23a/b increased adipogenic differentiation. Transmembrane protein 64 （Tmem64）, which has expression levels inversely related to those of miR-23a/b in aged and young mice, was identified as a major target of miR-23a/b during BMSC differentiation. In conclusion, our study suggests that miR-23a/b has a critical role in the regulation of mesenchymal lineage differentiation through the suppression of Tmem64.

Dorsal root ganglion neurons promote proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells

Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells remains unclear. No results at the cellular level have been reported. In this study, dorsal root ganglion neurons （sensory neurons） from Sprague-Dawley fetal rats were co-cultured with bone marrow mesenchymal stem cells transfected with green fluorescent protein 3 weeks after osteo- genic differentiation in vitro, while osteoblasts derived from bone marrow mesenchymal stem cells served as the control group. The rat dorsal root ganglion neurons promoted the prolifera- tion of bone marrow mesenchymal stem cell-derived osteoblasts at B and 5 days of co-culture, as observed by fluorescence microscopy. The levels of mRNAs for osteogenic differentiation-re- lated factors （including alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2） in the co-culture group were higher than those in the control group, as detected by real-time quantitative PCR. Our findings indicate that dorsal root ganglion neurons promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, which pro- vides a theoretical basis for in vitro experiments aimed at constructing tissue-engineered bone.

Dynamic Expression Profiles of Marker Genes in Osteogenic Differentiation of Human Bone Marrow-derived Mesenchymal Stem Cells

Objective To observe the expression profiles of osteoblast-related genes in human mesenchymal stem cells(MSCs) derived from bone marrow during osteogenic differentiation. Methods MSCs were induced to differentiate with MSC osteogenic differentiation medium for 7, 14, 21 and 28 days respectively. Alizarin Red staining was used to detect matrix mineralization. Expression of osteoblast-related genes, including osteocalcin, osteopontin, Runt-related transcription factor 2(Runx2), alkaline phosphatase and collagen type Ⅰ, was assessed with quantitative reverse transcription-polymerase chain reaction. Results On day 14 after induction of differentiation, cells were stained positively with Alizarin Red. The expression levels of these genes exhibited an upward trend as induction time was prolonged. Exposure to osteogenic differentiation medium less than 21 days did not significantly induce osteocalcin expression; osteocalcin expression levels in the differentiated cells induced for 21 and 28 days were 1.63 and 2.46 times as high as the undifferentiated cells respectively(all P<0.05). Stimulation with MSC osteogenic differentiation medium over 14 days significantly enhanced bone marrow-derived MSCs to express osteopontin and Runx2 genes(all P<0.05). Osteogenic differentiation medium could significantly induce the expressions of alkaline phosphatase and collagen type Ⅰgenes(all P<0.05). Their expressions reached the peak levels on day 21, which were increased more than 4- and 3-fold respectively. Conclusion Human bone marrow-derived MSCs could exhibit the sequential expression pattern of osteoblast marker genes during osteogenic differentiation in vitro.

Gene expression profiles associated with osteoblasts differentiated from bone marrow stromal cells

Objective:To study the changes of gene expression profiles associated with osteoblasts differentiated from rat bone marrow stromal cells in vitro by gene chip technique.Methods:rat Rone marrow stromal cells were isolated and cultured,and differentiation was induced by dexamethasone,β-glycerol phosphate and vitamin C.Cellular mRNA was extracted and reverse transcribed into cDNA,thus related genes expression differences were detected by gene expression profile chip.Results:Calcifying nodules were visible in the induced cells.There were27.7%genes expressed differentially,three times more than the normal and induced cells,and some genes were related to transcription,translation,glycosylation modification.Extracellular matrix,signal molecules and metabolism were up—regulated.Conclusions:The gene chip technique can be used to detect the multi-gene different expression in the differentiationinduceed rat BMSCs,and these differentially expressed genes are necessary genes related to rat BMSCs proliferation and induction of osteoblastic differentiation.

Effects of neurotrophin-3 intervention on on bone marrow mesenchymal stem cell osteoblast differentiation as well as cell proliferation and apoptosis

Objective:To study the effects of neurotrophin-3 (NT-3) intervention on bone marrow mesenchymal stem cell osteoblast differentiation as well as cell proliferation and apoptosis. Methods: Bone marrow mesenchymal stem cells were cultured and divided into control group, 25 ng/mL NT-3 group, 50 ng/mL NT-3 group and 100 ng/mL NT-3 group, they were treated with different doses of NT-3 for 24 h, and then osteoblast marker gene, cell proliferation gene and apoptosis gene expression were determined.Results: RUNX2, Osterix, ALP, OCN, BMP-2, Bcl-2, Nrf2, ERK1/2 and PCNA mRNA expression in 25 ng/mL NT-3 group, 50 ng/mL NT-3 group and 100 ng/mL NT-3 group were significantly higher than those in control group whereas Bim, Bax, Caspase-3, CHOP and Beclin1 mRNA expression were significantly lower than those in control group, and the larger the dose of NT-3, the higher the RUNX2, Osterix, ALP, OCN, BMP-2, Bcl-2, Nrf2, ERK1/2 and PCNA mRNA expression whereas the lower the Bim, Bax, Caspase-3, CHOP and Beclin1 mRNA expression.Conclusion: NT-3 intervention in bone marrow mesenchymal stem cells can promote osteoblast differentiation and cell proliferation and inhibit apoptosis.

Interaction between Schwann Cells and Osteoblasts In Vitro

Aim Given the well-known properties of Schwann cells in promoting nerve regeneration, transplanting Schwann cells into implant sockets might be an effective method to promote sensory responses of osseointegrated implants. The aim of this study was to evaluate the interaction between Schwann cells and osteoblasts. Methodology Schwann cells derived from the sciatic nerves of neonatal rat were co-culured with osteoblasts using Transwell inserts. The proliferation of Schwann cells in the co-culture system was evaluated using methylthiazol tetrazolium （MTT） colorimetric method. Moreover, the secretions and mRNA levels of brain-derived neurotrophic factor （BDNF） and nerve growth factor （NGF） were measured by enzyme-linked immunosorbent assay （ELISA） and quantitative real-time PCR, respectively. In order to test the effect of Schwann cells on osteoblasts, alkaline phosphatase （ALP） staining and Alizerin red staining were performed as well. Results Schwann cells, which were co-cultured with the osteoblasts, showed an intact proliferation during the observation period. Moreover, the gene expression and synthesis of BDNF and NGF were not impaired by the osteoblasts. Meanwhile, co-cultured osteoblasts exhibited a significant increase in the proliferation on day 3 and 6 （P〈 0.05）. Co-culture of these two types of cells also led to a more intense staining of ALP and an elevated number of calcified nodules. Conclusion These findings demonstrate that, in the in vitro indirect co-culture environment, Schwann cells can maintain their normal ability to synthesize neurotrophins, which then enhance the proliferation and differentiation of osteoblasts.

Effects of normobaric cyclic hypoxia exposure on mesenchymal stem-cell differentiation–pilot study on bone parameters in elderly

BACKGROUND Mesenchymal stem cells(MSC)of bone marrow are the progenitor of osteoblasts and adipocytes.MSC tend to differentiate into adipocytes,instead of osteoblasts,with aging.This favors the loss of bone mass and development of osteoporosis.Hypoxia induces hypoxia inducible factor 1αgene encoding transcription factor,which regulates the expression of genes related to energy metabolism and angiogenesis.That allows a better adaptation to low O2 conditions.Sustained hypoxia has negative effects on bone metabolism,favoring bone resorption.Yet,surprisingly,cyclic hypoxia(CH),short times of hypoxia followed by long times in normoxia,can modulate MSC differentiation and improve bone health in aging.AIM To evaluate the CH effect on MSC differentiation,and whether it improves bone mineral density in elderly.METHODS MSC cultures were induced to differentiate into osteoblasts or adipocytes,in CH(3%O2 for 1,2 or 4 h,4 d a week).Extracellular-matrix mineralization and lipid-droplet formation were studied in MSC induced to differentiate into osteoblast or adipocytes,respectively.In addition,gene expression of marker genes,for osteogenesis or adipogenesis,have been quantified by quantitative real time polymerase chain reaction.The in vivo studies with elderly(>75 years old;n=10)were carried out in a hypoxia chamber,simulating an altitude of 2500 m above sea level,or in normoxia,for 18 wk(36 CH sessions of 16 min each).Percentages of fat mass and bone mineral density from whole body,trunk and right proximal femur(femoral,femoral neck and trochanter)were assessed,using dual-energy X-ray absorptiometry.RESULTS CH(4 h of hypoxic exposure)inhibited extracellular matrix mineralization and lipid-droplet formation in MSC induced to differentiate into osteoblasts or adipocytes,respectively.However,both parameters were not significantly affected by the other shorter hypoxia times assessed.The longest periods of hypoxia downregulated the expression of genes related to extracellular matrix formation,in MSC induced to differentiate into osteoblasts.Interestingly,osteocalcin(associated to energy metabolism)was upregulated.Vascular endothelial growth factor an expression and low-density lipoprotein receptor related protein 5/6/dickkopf Wnt signaling pathway inhibitor 1(associated to Wnt/β-catenin pathway activation)increased in osteoblasts.Yet,they decreased in adipocytes after CH treatments,mainly with the longest hypoxia times.However,the same CH treatments increased the osteoprotegerin/receptor activator for nuclear factor kappa B ligand ratio in both cell types.An increase in total bone mineral density was observed in elderly people exposed to CH,but not in specific regions.The percentage of fat did not vary between groups.CONCLUSION CH may have positive effects on bone health in the elderly,due to its possible inhibitory effect on bone resorption,by increasing the osteoprotegerin/receptor activator for nuclear factor kappa B ligand ratio.

3D printing of osteocytic Dll4 integrated with PCL for cell fate determination towards osteoblasts in vitro

Since 3D printed hard materials could match the shape of bone,cell survival and fate determination towards osteoblasts in such materials have become a popular research target.In this study,a scaffold of hardmaterial for 3D fabrication was designed to regulate developmental signal(Notch)transduction guiding osteoblast differentiation.We established a polycaprolactone(PCL)and cell-integrated 3D printing system(PCI3D)to reciprocally print the beams of PCL and cell-laden hydrogel for a module.This PCI3D module holds good cell viability of over 87%,whereas cells show about sixfold proliferation in a 7-day culture.The osteocytic MLO-Y4 was engineered to overexpress Notch ligand Dll4,making up 25%after mixing with 75%stromal cells in the PCI3D module.Osteocytic Dll4,unlike other delta-like family members such as Dll1 or Dll3,promotes osteoblast differentiation and themineralization of primary mouse and a cell line of bone marrow stromal cells when cultured in a PCI3D module for up to 28 days.Mechanistically,osteocytic Dll4 could not promote osteogenic differentiation of the primary bone marrow stromal cells(BMSCs)after conditional deletion of the Notch transcription factor RBPjκby Cre recombinase.These data indicate that osteocytic Dll4 activates RBPjκ-dependent canonical Notch signaling in BMSCs for their oriented differentiation towards osteoblasts.Additionally,osteocytic Dll4 holds a great potential for angiogenesis in human umbilical vein endothelial cells within modules.Our study reveals that osteocytic Dll4 could be the osteogenic niche determining cell fate towards osteoblasts.This will open a new avenue to overcome the current limitation of poor cell viability and low bioactivity of traditional orthopedic implants.

Mechanical Sensitive Molecule MACF1 Promotes Osteoblast Differentiation

The decreased osteoblast differentiation associated with reduced bone formation is one main cause of microgravityinduced bone loss.Our previous studies have demonstrated that microtubule actin crosslinking factor 1(MACF1)is downregulated in association with the decreased osteoblast differentiation and bone formation under simulated microgravity conditions.These findings suggest that MACF1 is sensitive to mechanical condition and may be critical for osteoblast differentiation and bone formation.To verify this hypothesis,current study investigates the role and mechanism of MACF1 in regulatingosteoblast differentiation by adopting MACF1 knockdown(MACF1-KD)osteoblasts.The results showed that MACF1 knockdown suppressed mineralized nodules formation,alkaline phosphatase(ALP)activity,osteogenic gene expression andβ-catenin signaling transduction.Moreover,we used RNA sequencing(RNA-seq)and chromatin immunoprecipitation sequencing(ChIP-seq)to investigate further mechanism.Interestingly,we found that MACF1 sequesterd repressors of osteoblast differentiation in cytoplasm.In conclusion,MACF1 is sensitive to mechanical condition and plays key role in activatingβ-catenin signaling transduction and sequestering repressors of osteoblast differentiation,which further promotes osteoblast differentiation.

Osteogenic differentiation of mesenchymal stem cells promoted by overexpression of connective tissue growth factor

Objective:Large segmental bone defect repair remains a clinical and scientific challenge with increasing interest focusing on combining gene transfection with tissue engineering techniques.The aim of this study is to investigate the effect of connective tissue growth factor(CTGF) on the proliferation and osteogenic differentiation of the bone marrow mesenchymal stem cells(MSCs).Methods:A CTGF-expressing plasmid(pCTGF) was constructed and transfected into MSCs.Then expressions of bone morphogenesis-related genes,proliferation rate,alkaline phosphatase activity,and mineralization were examined to evaluate the osteogenic potential of the CTGF gene-modified MSCs.Results:Overexpression of CTGF was confirmed in pCTGF-MSCs.pCTGF transfection significantly enhanced the proliferation rates of pCTGF-MSCs(P<0.05).CTGF induced a 7.5-fold increase in cell migration over control(P<0.05).pCTGF transfection enhanced the expression of bone matrix proteins,such as bone sialo-protein,osteocalcin,and collagen type I in MSCs.The levels of alkaline phosphatase(ALP) activities of pCTGF-MSCs at the 1st and 2nd weeks were 4.0-and 3.0-fold higher than those of MSCs cultured in OS-medium,significantly higher than those of mock-MSCs and normal control MSCs(P<0.05).Overexpression of CTGF in MSCs enhanced the capability to form mineralized nodules.Conclusion:Overexpression of CTGF could improve the osteogenic differentiation ability of MSCs,and the CTGF gene-modified MSCs are potential as novel cell resources of bone tissue engineering.

Notch signaling stimulates osteogenic differentiation of human bone marrow-derived mesenchymal stem cells

Notch signaling is one of the most important pathways mediating cell determination and differentiation. In this study, the roles of Notch signal in the regulation of osteogenic differentiation of human bone marrow mesen-chymal stem cells (hMSCs) were investigated. The expression of Notch1, Jagged1 and DTX1 detected by reverse transcrip-tion polymerase chain reaction (RT-PCR) suggested that Notch signal might exhibit a physiological regulatory role in the differentiation of MSCs. Constitutive expression of the intracellular domain of Notch1 (ICN), the active form of Notch1 protein, can activate Notch signal in cells without ligands binding. hMSCs were isolated, expanded, and in-fected with retrovirus carrying green fluorescent protein (GFP) gene or ICN. Overexpression of ICN in hMSCs re-sulted in enhanced osteogenic differentiation induced by dexamethasone (Dex), which was characterized by an in-crease of cellular alkaline phosphatase (ALP) activity and calcium deposition. These results indicate that Notch stimu-lates differentiation of MSCs into osteoblasts.

柚皮苷防治骨质疏松症的分子机制

背景:近年研究表明,柚皮苷抗骨质疏松的研究大多停留在体内外实验当中,了解相关信号通路的作用机制以及相关蛋白与某些特定基因的表达是深入了解柚皮苷发挥抗骨质疏松症的重要途径。目前,中医药已被证实在抗骨质疏松方面具有显著作用,柚皮苷是骨碎补中的主要有效成分之一,其抗骨质疏松的有效性及作用机制逐渐得到学者们认可,其临床与基础研究逐渐被大家重视。目的:分析总结柚皮苷在体内外发挥抗骨质疏松作用的研究进展,为下一步研究其相关的作用机制提供一些思路。方法:检索中国知网、万方、维普数据库及PubMed数据库收录的相关文献,中文检索词为“柚皮苷,骨质疏松症,中药单体,发病机制,信号通路,骨髓间充质干细胞,成骨细胞,破骨细胞”等;英文检索词为“Naringin,Osteoporosis,Chinese medicine monomer,pathogenesis,Signal path,Bmscs,Osteoblast,Osteoclast”等,并根据研究需要确立相应的标准,对最终所得文献进行筛选,最终纳入69篇文献进行综述。结果与结论:(1)柚皮苷阻断了富含果糖饮食引起的破骨细胞和脂肪细胞数量的增加以及骨细胞和骨钙素(+)细胞数量的减少、并且通过促进成骨细胞和骨细胞分泌Sema3A,从而激活Wnt/β-catenin信号通路局部增强成骨细胞骨形成,同时抑制破骨细胞生成。(2)柚皮苷通过诱导成骨细胞自噬是一种重要的形式,然而自噬相关蛋白参与成骨细胞分化和骨形成,当成骨细胞缺乏自噬会降低矿化能力,并导致成骨细胞和破骨细胞数量不平衡,从而导致骨量丢失,骨密度下降。(3)搭载柚皮苷的复合支架可为骨缺损修复提供必要的载体,并且柚皮苷还能增加局部骨形态发生蛋白2和血管内皮生长因子的含量,从而加速新生骨组织的生长,具备优异的骨修复性能。(4)柚皮苷可调控ERK、PI3K/Akt和Wnt等相关信号通路来发挥调节骨代谢以及抑制氧化应激等作用,进而调控骨质疏松症,对该病起到良好的防治作用,但目前相关研究深度和广度不足,在未来应基于目前的机制研究,深入探究柚皮苷调控该病不同通路的具体机制及通路间相互作用,将有利于运用柚皮苷治疗骨质疏松症的多元发展。

miR-194-3p调控模拟微重力条件下致成骨细胞功能异常的实验研究

目的探讨模拟微重力环境下miR-194-3p对成骨细胞功能变化的调控作用,为极端力学环境下成骨细胞的力学响应机制提供理论基础。方法利用细胞旋转培养系统建立细胞水平微重力环境,分别采用MTT、RT-PCR、Western blot、荧光双染色法和茜素红染色法检测转染miR-194-3p抑制剂前后MC3T3-E1成骨细胞增殖、分化、凋亡和矿化的变化情况。结果模拟微重力环境下miR-194-3p表达上调,成骨细胞的增殖、分化和矿化均受到一定程度的抑制,同时促进了成骨细胞的凋亡。转染miR-194-3p抑制剂后,miR-194-3p表达显著下调,且能部分逆转由微重力导致的细胞成骨细胞增殖减弱、成骨分化标志物如ALP、OCN和COL-I基因和蛋白表达降低、骨矿化结节减少和成骨细胞凋亡数目增加的情况,说明miR-194-3p能有效改善微重力暴露下成骨细胞功能异常的情况。结论模拟微重力环境下miR-194-3p可能作为一种负调控因子,通过调控成骨细胞功能参与其力学响应的进程。

脯氨酰羟化酶2抑制剂cpd17对小鼠成骨前体细胞的影响

背景:脯氨酰羟化酶2抑制剂能够调节骨代谢,改善卵巢切除大鼠骨质疏松。cpd17是中国药科大学最新研发的一款小分子口服脯氨酰羟化酶2抑制剂,用于治疗肾性贫血疗效肯定,不良反应小,但是对骨形成和骨吸收的作用还不清楚。目的:探讨脯氨酰羟化酶2抑制剂cpd17对成骨前体细胞的影响。方法:采用cpd17处理C57BL/6小鼠成骨前体细胞,检测碱性磷酸酶活性和细胞外基质矿化程度,检测成骨、破骨相关标志物以及脯氨酰羟化酶2、低氧诱导因子1α的表达水平。使用低氧诱导因子1α通路抑制剂LW6抑制低氧诱导因子1α通路后,再次检测碱性磷酸酶活性和细胞外基质矿化程度,以及成骨和破骨分化相关标志物以及脯氨酰羟化酶2、低氧诱导因子1α的表达水平。结果与结论:cpd17能显著增强碱性磷酸酶活性和基质矿化程度,上调成骨分化相关标志物的表达,下调破骨分化相关标志物的表达,并上调低氧诱导因子1α表达,下调脯氨酰羟化酶2的表达。而LW6能明显减弱cpd17的作用。结果表明,脯氨酰羟化酶2抑制剂cpd17可通过激活低氧诱导因子1α信号通路促进成骨分化和抑制破骨分化。

成骨细胞线粒体移植促骨髓间充质干细胞体外增殖、迁移和成骨分化

为探究成骨细胞(OBs)线粒体移植对骨髓间充质干细胞(BMSCs)向成骨分化的影响,本研究体外人工提取BMSCs线粒体和OBs线粒体,分别移植入受体BMSCs.实验结果发现,接受成骨细胞线粒体的BMSCs表现出显著增强的增殖、迁移、抗凋亡和成骨能力.此外,接受成骨细胞线粒体的BMSCs胞内活性氧水平降低、氧气消耗速率上调、ATP产量增加.以上结果表明,(1)成骨细胞线粒体移植能够增强体外BMSCs功能,促进其向成骨分化;(2)相较于接受骨髓间充质干细胞线粒体,接受成骨细胞线粒体移植的受体BMSCs具有更强的有氧代谢能力以及更强的成骨分化能力,有望为骨生长与骨损伤修复提供一种候选方法 .

载槲皮素明胶微球对MC3T3-E1增殖和分化的影响

目的研究负载槲皮素的明胶三维多孔(G-quercetin)微球作为骨组织材料的可行性。方法利用乳化法制备负载槲皮素的多孔明胶微球,扫描电镜观察微球形态,通过免疫荧光染色、活死细胞染色和CCK-8、碱性磷酸酶(ALP)染色及茜素红染色检测微球的细胞毒性及其对小鼠胚胎成骨细胞前体细胞(MC3T3-E1)黏附、增殖及分化的影响,RT-PCR检测成骨相关基因Runx-2、ALP、OPN、OCN表达。结果扫描电镜结果显示制备的载槲皮素明胶三维微孔材料具有多孔结构。细胞黏附检测显示细胞能够在微球表面铺展良好。与对照组相比,活死细胞染色、CCK-8结果显示该微球无明显细胞毒性(P>0.05);与G-quercetin微球共培养的MC3T3-E1 ALP表达和体外矿化增加;PCR结果显示Runx-2、ALP、OCN、OPN表达明显增高(P<0.05)。结论载槲皮素明胶微球具有良好的生物相容性,能够促进MC3T3-E1体外成骨分化,有望作为新型骨组织工程生物材料应用于临床。

成骨诱导人牙周膜干细胞来源外泌体促进炎症微环境下人牙周膜干细胞成骨分化

背景:成骨诱导间充质干细胞来源外泌体具有较强的成骨分化能力,但是在炎症微环境下对人牙周膜干细胞成骨分化的影响尚不明确。目的:探究成骨诱导人牙周膜干细胞来源外泌体在炎症微环境下对人牙周膜干细胞成骨分化的影响。方法:收集离体牙并分离培养人牙周膜干细胞,成骨诱导3 d后提取外泌体。将人牙周膜干细胞分为4组:对照组加入成骨诱导培养基,外泌体组加入含5μg/mL外泌体的成骨诱导培养基,炎症模型和炎症模型+外泌体组以1μg/mL脂多糖处理24 h构建细胞炎症微环境,炎症模型组在脂多糖处理后加入成骨诱导培养基,炎症模型+外泌体组在脂多糖处理后加入含5μg/mL外泌体的成骨诱导培养基。通过茜素红以及碱性磷酸酶染色法检测各组人牙周膜干细胞的成骨分化能力;实时荧光定量PCR与免疫印迹法检测各组人牙周膜干细胞中Runt相关转录因子2、骨桥蛋白、成骨细胞特异性转录因子Osterix(OSX)和wnt通路相关蛋白β-catenin的表达。结果与结论:(1)与对照组相比,炎症模型组碱性磷酸酶染色相对面积、矿化结节染色相对面积以及Runt相关转录因子2、骨桥蛋白、OSX的表达量显著降低(P <0.05);(2)与炎症模型组相比,炎症模型+外泌体组碱性磷酸酶染色相对面积、矿化结节染色相对面积以及Runt相关转录因子2、骨桥蛋白、OSX的表达显著升高(P <0.05);(3)与对照组相比,炎症模型组wnt通路相关蛋白β-catenin表达量显著增加(P <0.05);与炎症模型组相比,炎症模型+外泌体组β-catenin表达量显著降低(P <0.05)。结果表明,成骨诱导人牙周膜干细胞来源外泌体可促进炎症微环境下人牙周膜干细胞的成骨分化,其作用机制可能与wnt/β-catenin信号通路有关。

锌指蛋白-36缺陷抑制小鼠的成骨细胞分化:基于激活ERK/ MAPK通路

目的探究锌指蛋白-36(ZFP36)对成骨细胞分化的调控作用及机制。方法通过提取小鼠原代骨髓间充质干细胞,结合小鼠成骨细胞前体细胞系MC3T3-E1,在体外成骨分化诱导状态下观察Zfp36(编码ZFP36)的表达变化。通过干扰RNA技术构建Zfp36缺陷的细胞,观察成骨分化作用的改变。通过第二代转录组测序技术探究Zfp36缺陷细胞成骨分化过程中的转录组水平改变。通过ERK/MAPK信号抑制分子U0126验证Zfp36缺陷对成骨分化作用的调控机制。结果小鼠原代骨髓间充质细胞以及MC3T3-E2细胞中Zfp36表达在成骨分化0~14d过程中呈逐渐升高趋势,在第7天到达峰值时较第0天升高3.85倍(P<0.0001)。抑制上述细胞Zfp36的表达后,成骨分化过程中碱性磷酸酶染色及茜素红染色弱于对照组,成骨分化标志基因Alpl(P<0.01)、Sp7(P<0.001)、Bglap(P<0.01)、Ibsp(P<0.0001)表达显著减弱。转录本测序结果提示Zfp36缺陷细胞的下调基因富集到骨矿化相关基因集中,且与ERK信号相关。蛋白表达检测显示Zfp36缺陷细胞的磷酸化ERK蛋白比例较对照组升高2.1倍(P=0.0274)。通过分子化合物U0126抑制Zfp36缺陷细胞中被激活的ERK/MAPK信号,可观察到表型挽救现象,并且呈剂量依赖。Zfp36缺陷细胞在10μmol/L度U0126作用下碱性磷酸酶染色增强,成骨细胞分化标志基因Runx2(P<0.05)及Bglap(P<0.05)表达显著增高。结论ZFP36参与了小鼠成骨细胞的分化调控过程,Zfp36缺陷会引起ERK/MAPK信号通路的激活,进而抑制成骨细胞向骨细胞的分化。

人诱导多能干细胞成骨分化的研究进展

骨骼疾病如骨质疏松、骨关节炎等已成为亟待解决的人类健康问题,细胞治疗及组织工程技术被认为是理想的治疗方法之一。人诱导多能干细胞(human induced pluripotent stem cells,hiPSCs)具备体外长期自我更新和分化所有三胚层来源体细胞的独特功能,已成为目前最有前景的成骨细胞来源。因此,需要构建成分明确的hiPSCs体外成骨向诱导分化体系,获得符合临床应用要求的成骨样细胞。许多团队在促进hiPSCs向成骨分化成熟的直接路径和经间充质干细胞的间接路径方面取得了实质性的进展,本文针对这两类成骨分化路径及其应用现状进行综述,以期为骨再生技术提供参考。现有研究借助拟胚体法和单层诱导法,基于生物材料,构建可支持hiPSCs体外培养和成骨向诱导分化体系。然而,目前的研究主要存在成分不明确,分化效率低等局限,基于特定化合物严格调控的分阶段式和三维定向诱导体系是未来的主要研究方向。