RNA Interference-Mediated Gene Silencing of Vascular Endothelial Growth Factor

OBJECTIVE To inhibit the expression of the vascular endothelial growth factor (VEGF) by RNA interference, and to observe the effect in different cells line. METHODS Using the services of E-RNAi, we designed and constructed two kinds of shRNAs expression vectors which were aimed at the VEGF gene. These vectors were then transfected into HEK293, colon cancer HT29, Hela and HepG2 cells by LipofectamineTM 2000. The level of VEGF mRNA was determined by RT-PCR and Northern blotting and the VEGF expression was examined by immunofluoresence staining. RESULTS The two kinds of VEGF specific shRNAs expression vectors were found to efficiently inhibit the expression of VEGF in HEK293 and HT29 cells by RT-PCR analysis, with inhibition rates of 72% and 42%, respectively; but the inhibition rates were reduced to 28% in Hela cells and 13% in HepG2 cells. Northern blotting showed that the inhibition rates of VEGF mRNA expression were 88% and 89% in HEK293 and HT29 cells, respectively. The inhibition rate of VEGF protein expression in HT29 cells was 73% based on immunofluoresence staining. CONCLUSION The expression of VEGF was inhibited by RNA interference, but differed with various cells lines, showing that RNA interference was cell-line dependent.

Molecular pathogenesis and therapeutic strategies of human osteosarcoma

Osteosarcoma（OS）is a devastating illness with rapid rates of dissemination and a poor overall prognosis,despite aggressive standard-of-care surgical techniques and combination chemotherapy regimens.Identifying the molecular mechanisms involved in disease pathogenesis and progression may offer insight into new therapeutic targets.Defects in mesenchymal stem cell differentiation,abnormal expression of oncogenes and tumor suppressors,and dysregulation within various important signaling pathways have all been implicated in development of various disease phenotypes.As such,a variety of basic science and translational studies have shown promise in identifying novel markers and modulators of these disease-specific aberrancies.Born out of these and similar investigations,a variety of emerging therapies are now undergoing various phases of OS clinical testing.They broadly include angiogenesis inhibitors,drugs that act on the bone microenvironment,receptor tyrosine kinase inhibitors,immune system modulators,and other radio-or chemo-sensitizing agents.As new forms of drug delivery are being developed simultaneously,the possibility of targeting tumors locally while minimizing systemic toxicityis is seemingly more achievable now than ever.In this review,we not only summarize our current understanding of OS disease processes,but also shed light on the multitude of potential therapeutic strategies the scientific community can use to make long-term improvements in patient prognosis.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in develop-ment and adult tissue homeostasis across species.Wnt proteins are secreted,lipid-modified signaling molecules that activate the canonical(β-catenin dependent)and non-canonical(β-catenin independent)Wnt signaling pathways.Cellular behaviors such as proliferation,differ-entiation,maturation,and proper body-axis specification are carried out by the canonical pathway,which is the best characterized of the known Wnt signaling paths.Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues.This includes but is not limited to embryonic,hematopoietic,mesenchymal,gut,neural,and epidermal stem cells.Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties.Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders.Not surprisingly,aberrant Wnt signaling is also associated with a wide variety of diseases,including cancer.Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation,epithelial-mesenchymal transition,and metastasis.Altogether,advances in the understand-ing of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway.Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt,this review aims to summarize the cur-rent knowledge of Wnt signaling in stem cells,aberrations to the Wnt pathway associated with diseases,and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

ATDC5来源外泌体包载小分子药物5Z-7-Oxozeaenol治疗骨关节炎

骨关节炎(osteoarthritis,OA)是一种常见的退行性关节疾病。研究表明,TAK1的抑制剂小分子药物5Z-7-Oxozeaenol(5Z-7),用于治疗OA时直接将药物进行频繁关节腔注射,药物的治疗效果有限。本研究选取小鼠胚胎瘤成软骨细胞系(ATDC5),是一种理想的成软骨细胞模型,其增殖速度和培养稳定性均优于间充质干细胞,用于提取外泌体作为药物的载体。本研究提取ATDC5来源的外泌体(ATDC5-Exos),包载药物5Z-7。在炎性细胞因子诱导大鼠软骨细胞模型中,载药外泌体可以促进合成代谢相关基因Col2a1、Sox9的表达,抑制分解代谢相关基因Adamts5、Mmp13的表达。本研究使用8周龄雄性小鼠,行前交叉韧带离断术(ACLT)诱导OA小鼠模型,关节腔注射外泌体或载药外泌体治疗,取膝关节石蜡切片进行组织学评估。结果显示,载药外泌体可缓解创伤后OA模型的病理表型。结合Micro-CT影像学结果显示,治疗能改善ACLT术后膝关节软骨下骨骨小梁的流失和骨赘减少,关节表面更为光滑。本研究证实,ATDC5-Exos包载药物5Z-7在体内和体外实验中均可缓解OA表型。外泌体包载递送5Z-7减少了药物的用量和给药频率,且药物和外泌体可以叠加治疗改善OA的效果。

Engineered nucleus-free mesenchymal stem cells (MSCs) for the targeted delivery of therapeutics to disease site

Specialized therapeutic delivery, or use of pharmaceuticals and other biomaterials to target specific parts of the body or diseased tissue, has long been sought as an ideal way of treating human diseases. A recent article published in Nature Biomedical Engineering revealed an innovative strategy to engineer nucleus-free human mesenchymal stem cells (MSCs) for targeted delivery of therapeutics to disease site.1 MSCs have emerged as promising vehicles of therapeutic delivery.2,3 MSCs are undifferentiated pluripotent stem cells derived from areas such as bone marrow and adipose tissue.4,5 MSCs are sought after for their chemotaxis, or ability to home towards a chemical stimulus, and capacity for modification with elements such as chemoattractant receptors and adhesion molecules.1 These properties allow for site-specific and minimally-invasive therapeutic administration and treatment.

Corrigendum to “Characterization of the essential role of bone morphogenetic protein 9 (BMP9) in osteogenic differentiation of mesenchymal stem cells (MSCs) through RNA interference” [Genes & Diseases 5(2018):172–184]

The authors regret having several image assembly errors.Specifically,in Figure 3A panel b,the image for "AdsimB9-4 only"group was erroneously duplicated with an overlapping image from the"AdRFp"group;and the image for"AdsimB9-1+BMP9"groupwas erroneouslyduplicatedwithan overlapping image from"AdsimB9-8+BMP9"group.In Figure 4Apanel a,the images for"BMP9"group and "BMP9+simB9-4"group were erroneously duplicated with an overlapping image from"simB9-4"group.In Figure 5A,the image for"BMP9+simB9-4/Day3"group was erroneously duplicated with an overlapping image from"BMP9+simB9-7/Day3"group;and the image for"BMP9+simB9-4/Day5"group was erroneously duplicated with an overlapping image from an unrelated experiment.In Figure 6B,the image for"BMP9+simB9-7/Day 11"group was erroneously duplicated with an overlapping image from the"BMP9+simB9-4/Day 11"group.

Bone Morphogenic Protein 9(BMP9)/Growth Differentiation Factor 2(GDF2)modulates mouse adult hippocampal neurogenesis by regulating the survival of early neural progenitors

Adult neurogenesis occurs in two specialized regions of the mammalian brain,the subventricular zone(SVZ)and the subgranular zone(SGZ)of the dentate gyrus(DG).^(1)Adult hippocampal neural stem cells(NSCs),referred to as Type 1 cells represented by radial glia-like cells(RGLs),generate Type 2 cells that are divided into Type 2a and Type 2 b subpopulations,the latter of which give rise to Type 3 cells(neuroblasts).

Corrigendum to “The development of a sensitive fluorescent protein-based transcript reporter for high throughput screening of negative modulators of lncRNAs” [Genes & Diseases 5 (2018) 62–74]

The authors regret having an image assembly error in Figure 5Ca,in which the image for the "Oh dBiFP-AdRFp"group was erroneously duplicated with an overlapping image from the"36h BiFP dBIFP-AdR-simH19"group.We confirm the error is restricted to the image assembly,and the underlying data and conclusions are correct and unchanged.The authors would like to apologize for any inconvenience caused.

Corrigendum to “Establishment and functional characterization of the reversibly immortalized mouse glomerular podocytes (imPODs)” [Genes & Diseases 5 (2018) 137–149]

The authors regret having an image assembly error in Figure 3A,in which the image for "imPOD Synaptopodin DAPl stain"groupwas erroneouslyduplicatedwiththe imagefrom the"tsPOD-33C SynaptopodinDAPIstain"group.We confirm the error is restricted to the image assembly,and the underlying data and conclusions are correct and unchanged.The authors would like to apologize for any inconvenience caused.

A simplified noncryogenic strategy to transport mesenchymal stem cells: Potential applications in cell therapy and regenerative medicine

With the rapid advances in stem cell research and po-tential cell-based therapies,there is an urgent need to develop safe and reliable cell transport strategies.Except for autologous stem cell-based therapies,allogeneic stem cell therapies and ex vivo genetically engineered cell therapies would require safe,efficient,and reliable cell preservation and transport methods.

RNA干扰技术对肝癌细胞内源survivin基因表达的影响

应用RNA干扰技术(RNAi)研究针对凋亡抑制因子survivin的siRNA抑制肝癌细胞株内源survivin基因的表达.转染重组质粒pshRNA survivin至肝癌细胞株SMMC 772 1,通过免疫荧光、蛋白质印迹和半定量RT PCR检测survivin蛋白表达及mRNA转录水平的变化.结果表明:构建的三种重组质粒pshRNA survivin1/2/3均能明显抑制survivin基因的表达;应用免疫荧光检测survivin基因的表达,转染重组质粒pshRNA survivin的实验组survivin荧光强度明显低于转染载体pTZU6 +1和pshRNA GFP对照组;蛋白质印迹结果表明,重组质粒pshRNA survivin明显抑制survivin蛋白的表达,抑制率为 6 2 %～ 78%,通过半定量RT PCR检测到survivin基因mRNA转录明显减少,抑制率为5 7%～ 6 4 %.由上述结果可以得出结论:重组质粒pshRNA survivin可明显抑制SMMC 772 1细胞内源survivin的表达和mRNA的转录。

shRNA表达载体构建方法的优化

目的探讨shRNA表达载体的构建方法 ,以加速RNA干扰研究的进程。方法对shRNA表达载体的构建过程进行分析和监测 ,并加以优化。结果发现shRNA表达载体构建的退火过程容易产生障碍 ,经优化退火缓冲液的NaCl含量后 ,能明显提高退火效率及shRNA表达载体构建的成功率。结论shRNA表达载体构建的退火过程需加以关注 ,退火缓冲液中NaCl含量应提高至 2 0

钙结合蛋白S100A2对Wnt/β-catenin信号途径活性的上调作用

目的研究钙结合蛋白S100A2对Wnt/β-catenin信号途径活性的影响,并探讨其可能的机制。方法原核诱导表达GST-hS100A2,经纯化后加入骨肉瘤细胞株MG63和人结肠癌细胞株HCT116的培养液中,Western blot检测细胞中β-catenin含量的变化;荧光素酶活性分析法检测S100A2对HEK293细胞中β-catenin/TCF4活性的影响;以表达GSK-3β、DVL、Axin的相应质粒分别转染HEK293细胞,GST-Pulldown/Western blot实验检测S100A2与这些蛋白质和β-catenin之间的相互作用。结果S100A2使MG63和HCT116细胞中β-catenin含量增加、β-catenin/TCF4活性增强;S100A2分别与β-catenin和GSK-3β之间存在相互作用,而与DVL和Axin之间则未发现相互作用。结论S100A2可以上调Wnt/β-catenin信号途径的活性,其机制可能涉及S100A2与β-catenin和GSK-3β之间的相互作用。

RNA干扰抑制结肠癌细胞血管内皮生长因子表达

目的:应用RNA干扰技术抑制结肠癌血管内皮生长因子(VEGF)表达。方法:将VEGF基因作为RNA干扰的靶区,通过E-RNAi网上提供的服务,设计两个特异的RNA干扰序列,将其装入含U6启动子的载体上,构建成抗VEGF基因的小发夹样RNA(shRNA)表达载体,再转染人结肠癌细胞HT29,通过RT-PCR、Northern blotting、免疫荧光和Western blotting,观察VEGF表达受抑的程度。结果:成功构建了两种抗VEGF基因的shRNA表达载体,RT-PCR、Northern blotting、免疫荧光和Western blotting,均发现其能明显抑制HT29细胞VEGF基因的表达,抑制率分别达42%、88%、73%和82%。结论:针对VEGF基因的shRNA表达载体能够明显抑制结肠癌细胞VEGF基因的表达。

抑制Dicer基因对shRNA功能发挥的影响

本文将Dicer基因的RNA酶III结构域作为靶区,设计并构建了两个抗Dicer基因的小发夹样RNA(shRNA)表达载体,将其转染2215、结肠癌TC细胞和基因组中整合有绿色荧光蛋白基因(GFP)的HepG2A9细胞,通过RT-PCR评价RNA干扰抑制Dicer基因表达的效率;当HepG2A9细胞Dicer基因表达被上述RNA干扰抑制时,再转染抗GFP的shRNA表达载体,通过RT-PCR和荧光显微镜观察GFP表达水平。结果显示,在不同细胞系中,这两个抗Dicer基因shRNA表达载体,均能明显抑制Dicer基因的表达;当Dicer基因受抑时,后续转染抗GFP的shRNA表达载体不能有效抑制GFP的表达。结果表明,抗Dicer基因shRNA表达载体,能够明显抑制Dicer基因的表达;shRNA表达载体的功能发挥需要Dicer酶的直接参与。

Mesenchymal stem cells: Molecular characteristics and clinical applications

Mesenchymal stem cells (MSCs) are non-hematopoietic stem cells with the capacity to differentiate into tissues of both mesenchymal and non-mesenchymal origin. MSCs can differentiate into osteoblastic, chondrogenic, and adipogenic lineages, although recent studies have demonstrated that MSCs are also able to differentiate into other lineages, including neuronal and cardiomyogenic lineages. Since their original isolation from the bone marrow, MSCs have been successfully harvested from many other tissues. Their ease of isolation and ex vivo expansion combined with their immunoprivileged nature has made these cells popular candidates for stem cell therapies. These cells have the potential to alter disease pathophysiology through many modalities including cytokine secretion, capacity to differentiate along various lineages, immune modulation and direct cell-cell interaction with diseased tissue. Here we first review basic features of MSC biology including MSC characteristics in culture, homing mechanisms, differentiation capabilities and immune modulation. We then highlight some in vivo and clinical evidence supporting the therapeutic roles of MSCs and their uses in orthopedic, autoimmune, and ischemic disorders.

Colorectal cancer and dysplasia in inflammatory bowel disease

Both ulcerative colitis and Crohn’s disease carry an increased risk of developing colorectal cancer. Established risk factors for cancer among patients with inflammatory bowel disease (IBD) include the younger age at diagnosis, greater extent and duration of disease, increased severity of inflammation, family history of colorectal cancer and coexisting primary sclerosing cholangitis. Recent evidence suggests that current medical therapies and surgical techniques for inflammatory bowel disease may be reducing the incidence of this complication. Nonetheless heightened vigilance and a careful, comprehensive approach to prevent or minimize the complications of invasive cancer are warranted in this unique cohort of patients. Current guidelines for the prevention and early detection of cancer in this high risk population are grounded in the concept of an inflammation-dysplasia- carcinoma sequence. A thorough understanding of the definition and natural history of dysplasia in IBD, as well as the challenges associated with detection and interpretation of dysplasia are fundamental to developing an effective strategy for surveillance and prevention, and understanding the limitations of the current approach to prevention. This article reviews the current consensus guidelines for screening and surveillance of cancer in IBD, as well as presenting the evidence and rationale for chemoprevention of cancer and a discussion of emerging technologies for the detection of dysplasia.

Adenovirus-mediated gene delivery:Potential applications for gene and cell-based therapies in the new era of personalized medicine

With rapid advances in understanding molecular pathogenesis of human diseases in the era of genome sciences and systems biology,it is anticipated that increasing numbers of therapeutic genes or targets will become available for targeted therapies.Despite numerous setbacks,efficacious gene and/or cell-based therapies still hold the great promise to revolutionize the clinical management of human diseases.It is wildly recognized that poor gene delivery is the limiting factor for most in vivo gene therapies.There has been a long-lasting interest in using viral vectors,especially adenoviral vectors,to deliver therapeutic genes for the past two decades.Among all currently available viral vectors,adenovirus is the most efficient gene delivery system in a broad range of cell and tissue types.The applications of adenoviral vectors in gene delivery have greatly increased in number and efficiency since their initial development.In fact,among over 2000 gene therapy clinical trials approved worldwide since 1989,a significant portion of the trials have utilized adenoviral vectors.This review aims to provide a comprehensive overview on the characteristics of adenoviral vectors,including adenoviral biology,approaches to engineering adenoviral vectors,and their applications in clinical and preclinical studies with an emphasis in the areas of cancer treatment,vaccination and regenerative medicine.Current challenges and future directions regarding the use of adenoviral vectors are also discussed.It is expected that the continued improvements in adenoviral vectors should provide great opportunities for cell and gene therapies to live up to its enormous potential in personalized medicine.

The versatile functions of Sox9 in development,stem cells,and human diseases

The transcription factor Sox9 was first discovered in patients with campomelic dysplasia,a haploinsufficiency disorder with skeletal deformities caused by dysregulation of Sox9 expression during chondrogenesis.Since then,its role as a cell fate determiner during embryonic development has been well characterized;Sox9 expression differentiates cells derived from all three germ layers into a large variety of specialized tissues and organs.However,recent data has shown that ectoderm-and endoderm-derived tissues continue to express Sox9 in mature organs and stem cell pools,suggesting its role in cell maintenance and specification during adult life.The versatility of Sox9 may be explained by a combination of posttranscriptional modifications,binding partners,and the tissue type in which it is expressed.Considering its importance during both development and adult life,it follows that dysregulation of Sox9 has been implicated in various congenital and acquired diseases,including fibrosis and cancer.This review provides a summary of the various roles of Sox9 in cell fate specification,stem cell biology,and related human diseases.Ultimately,understanding the mechanisms that regulate Sox9 will be crucial for developing effective therapies to treat disease caused by stem cell dysregulation or even reverse organ damage.

BMP signaling in mesenchymal stem cell differentiation and bone formation

Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily and have diverse functions during development and organogenesis. BMPs play a major role in skeletal development and bone formation, and disruptions in BMP signaling cause a variety of skeletal and extraskeletal anomalies. Several knockout models have provided insight into the mechanisms responsible for these phenotypes. Proper bone formation requires the differentiation of osteoblasts from mesenchymal stem cell (MSC) precursors, a process mediated in part by BMP signaling. Multiple BMPs, including BMP2, BMP6, BMP7 and BMP9, promote osteoblastic differentiation of MSCs both in vitro and in vivo. BMP9 is one of the most osteogenic BMPs, yet it is a poorly characterized member of the BMP family. Several studies demonstrate that the mechanisms controlling BMP9-mediated osteogenesis differ from other osteogenic BMPs, but little is known about these specific mechanisms. Several pathways critical to BMP9-mediated osteogenesis are also important in the differentiation of other cell lineages, including adipocytes and chondrocytes. BMP9 has also demonstrated translational promise in spinal fusion and bone fracture repair. This review will summarize our current knowledge of BMP-mediated osteogenesis, with a focus on BMP9, by presenting recently completed work which may help us to further elucidate these pathways.