Li Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 182-202). / Abstracts in English and Chinese. / Abstract --- p.i / 中文摘要 --- p.iii / Acknowledgements --- p.v / List of Abbreviations --- p.vi / CONTENTS --- p.viii / Chapter Chapter 1 --- General introduction --- p.1 / Chapter 1.1 --- Alkaline phosphatase --- p.1 / Chapter 1.1.1 --- Distribution --- p.1 / Chapter 1.1.2 --- Molecular characteristics of alkaline phosphatase --- p.4 / Chapter 1.1.3 --- Properties of alkaline phosphatase --- p.8 / Chapter 1.1.4 --- Role of alkaline phosphatase --- p.10 / Chapter 1.2 --- Mouse embryonic brain development --- p.18 / Chapter 1.2.1 --- General developing process --- p.18 / Chapter 1.2.2 --- The crainal nerve nuclei in the embryonic mouse brainstem --- p.20 / Chapter 1.2.3 --- The process of neurogenesis in central nerve system --- p.22 / Chapter 1.3 --- Alkaline phosphatase expressed in developing neural tube --- p.26 / Chapter 1.4 --- Summary --- p.30 / Chapter 1.5 --- Objectives of study --- p.31 / Chapter Chapter 2 --- AP expression pattern in embryonic mouse brainstem --- p.33 / Chapter 2.1 --- Introduction --- p.33 / Chapter 2.1.1 --- AP expressed in developing neural tube --- p.33 / Chapter 2.1.2 --- Methods for alkaline phosphatase detection --- p.35 / Chapter 2.2 --- Materials and methods --- p.39 / Chapter 2.2.1 --- Animal and procedure --- p.39 / Chapter 2.2.2 --- Preparation of tissue sections and histochemistry --- p.39 / Chapter 2.2.3 --- Electron microscopy study of AP location --- p.41 / Chapter 2.3 --- Results --- p.42 / Chapter 2.3.1 --- Histochemical demonstration of AP --- p.42 / Chapter 2.3.2 --- Stage-specificity and tissue-specificity of AP activity in the neural tube --- p.43 / Chapter 2.3.3 --- Cytochemical localization of AP activity --- p.46 / Chapter 2.3.4 --- Sencitivity to pH of the histochemical staining for AP --- p.46 / Chapter 2.3.5 --- Inactivation of AP activity --- p.47 / Chapter Chapter 3 --- Quantitative studies of AP activity in embryonic mouse brainstem --- p.48 / Chapter 3.1 --- Introduction --- p.48 / Chapter 3.1.1 --- Basic knowledge about enzyme kinetic study --- p.48 / Chapter 3.1.2 --- Enzyme assay for alkaline phosphatase --- p.50 / Chapter 3.2 --- Materials and methods --- p.52 / Chapter 3.2.1 --- Animals and sample preparation --- p.52 / Chapter 3.2.2 --- Measurement of AP activities --- p.53 / Chapter 3.2.3 --- Data analysis --- p.54 / Chapter 3.3 --- Results --- p.54 / Chapter 3.3.1 --- "Determination of reaction duration, initial velocity and Km of AP activity" --- p.54 / Chapter 3.3.2 --- Comparision of AP activity in the brainstem and cortex and at different stages --- p.55 / Chapter 3.3.3 --- Effects of physical and chemical factors on AP activity --- p.55 / Chapter Chapter 4 --- Electrophoresis study of AP activity --- p.57 / Chapter 4.1 --- Introduction --- p.57 / Chapter 4.2 --- Materials and methods --- p.60 / Chapter 4.2.1 --- AP extraction --- p.60 / Chapter 4.2.2 --- Polyacrylamide gel electrophoresis (PAGE) --- p.61 / Chapter 4.2.3 --- Detection of AP activity --- p.61 / Chapter 4.3 --- Results --- p.62 / Chapter 4.3.1 --- Demonstration of AP activity on the gels --- p.62 / Chapter 4.3.2 --- Comparison of AP from the brain at different stages --- p.62 / Chapter 4.3.3 --- "Comparison of AP in the embryonic brainstem with those in the adult mouse placenta, kidney, liver and intestine" --- p.63 / Chapter 4.3.4 --- Effect of heating and chemical factors on AP activity in the embryonic brainstem --- p.63 / Chapter Chapter 5 --- Study of the cell types expressing AP activity --- p.65 / Chapter 5.1 --- Introduction --- p.65 / Chapter 5.2 --- Materials and methods --- p.67 / Chapter 5.2.1 --- Materials --- p.67 / Chapter 5.2.2 --- Immunostaining of AP in the embryonic brainstem --- p.68 / Chapter 5.2.3 --- Double staining for AP and cells markers --- p.70 / Chapter 5.3 --- Results --- p.70 / Chapter 5.3.1 --- Effectiveness of anti-TNAP antibody on the embryonic mouse brain --- p.70 / Chapter 5.3.2 --- Expression pattern of different neural cell markers at E13.5 --- p.71 / Chapter 5.3.3 --- Co-localization of AP and specific cell markers in E13.5 brain --- p.72 / Chapter Chapter 6 --- Discussion --- p.74 / Chapter 6.1 --- Stage-dependence and tissue-specificity of AP expression in the developing mouse brainstem --- p.75 / Chapter 6.2 --- Possible molecular nature of AP expressed in the developing mouse brainstem --- p.80 / Chapter 6.3 --- The possible cell types that express the enzyme activity --- p.83 / "Figures, Tables, Graphs and Legends" --- p.87 / Appendices --- p.165 / Appendix A: Sources of materials --- p.165 / Appendix B: The process of sample for staining --- p.167 / Appendix C: Protocol of histochemical staining for AP --- p.170 / Appendix D: Protocol of electron microscopy study for AP activity --- p.172 / Appendix E: Protocol of enzyme assay for AP activity --- p.174 / Appendix F: Protocol of immunostaining (ABC method) --- p.175 / Appendix G: Protocol of double staining with fluorescent detection --- p.177 / Appendix H: Protocol of electrophoresis analysis for AP --- p.179 / References --- p.182

Yau Fung-wan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 147-183). / Abstracts in English and Chinese. / Acknowledgements --- p.iii / Publications --- p.iv / Abbreviations --- p.vii / Appendix Some cell surface antigens expressed on hematopoietic cells --- p.ix / Abstract --- p.x / Chapter Chapter One --- Introduction --- p.1 / Chapter Section A --- Sources of blood stem cells for transplantation --- p.1 / Chapter Section B --- Hematopoiesis --- p.7 / Chapter Section C --- Human CD34+ blood cells --- p.15 / Chapter Section D --- Human stem and progenitor cells in neonates --- p.19 / Chapter Section E --- Methods of CD34 detection --- p.23 / Chapter Section F --- Adhesion molecule: migratory properties of hematopoietic stem and progenitor cells --- p.33 / Chapter Section G --- Project objectives --- p.37 / Chapter Chapter Two --- Materials and Methods --- p.38 / Chapter Section A --- Quality and quantity of CD34+ cells in neonatal blood --- p.38 / Chapter Section B --- Kinetics of hematopoietic stem and progenitor cellsin human neonatal blood after birth --- p.48 / Chapter Section C --- Enumeration of long term culture initiating cells by limiting dilution assay --- p.56 / Chapter Chapter Three --- Results & Discussion --- p.61 / Chapter Section A --- Characterization of hematopoietic stem and progenitor cells in neonatal blood --- p.61 / Results --- p.61 / Discussion --- p.78 / Chapter Section B --- Kinetics of hematopoietic stem and progenitor cellsin neonatal blood --- p.88 / Results --- p.88 / Discussion --- p.119 / Chapter Section C --- Comparison of CD34+ cell enumeration by flow cytometry using two antibodies and two protocols --- p.125 / Results --- p.125 / Discussion --- p.129 / Conclusion --- p.131 / Future prospective --- p.133 / References --- p.134

Yau, Ka Long. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 97-113). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

肌腱損傷發生率高，並且癒合結果很不理想，因為少量的肌腱細胞缺乏有效的修復能力，僅僅通過瘢痕形成來癒合, 肌腱瘢痕癒合難以恢復原本的肌腱組織結構及力學特性。目前，國內外臨床上治療肌腱損傷的方法很多，包括藥物、物理治療、手術等，這些並不能獲得滿意的療效。因此，如何採用肌腱組織工程技術迅速、安全、有效的修復肌腱損傷已成為運動醫學領域急需解決的重要問題。 / 有研究表明，骨髓間充質幹細胞、表皮成纖維細胞、肌腱細胞和胚胎幹細胞通過肌腱組織工程技術用於肌腱修復及再生取得了不錯的療效。但是，這些來源的細胞存在分化效率低，形成畸胎瘤和異位骨化等風險。近來，有研究報導可從人、小鼠、大鼠和兔的肌腱組織中分離培養出幹細胞，可作為肌腱組織工程種子細胞的一種新選擇，用於肌腱修復和再生。對於間充質幹細胞的成肌腱分化，有研究報導結締組織生長因子（CTGF）和抗壞血酸（維生素C的一種形式）在膠原及細胞外基質合成、調節細胞成肌腱分化方面扮演者重要的角色。 / 本研究的旨在：（1）在大鼠髕腱損傷模型中，證實肌腱幹細胞可作為一種新的幹細胞來源用於肌腱修復；（2）檢驗結締組織生長因子和抗壞血酸能在體外促進肌腱幹細胞的成肌腱分化；（3）嘗試通過肌腱幹細胞的成肌腱分化過程在體外構建不含外源性支架的肌腱樣組織；（4）探索該肌腱樣組織在大鼠髕腱損傷模型中是否可以促進肌腱癒合。 / 在大鼠急性髕腱損傷動物模型中，與對照組相比，肌腱幹細胞組具有更好的膠原排列，顯著增高的最大張力和楊氏模量，表明肌腱幹細胞可作為一種新的幹細胞來源用於肌腱損傷的修復。結締組織生長因子和抗壞血酸體外誘導肌腱幹細胞2周後，可顯著增加Tenomodulin, Scleraxis, Thbs4, I型膠原等肌腱相關基因的表達以及膠原蛋白的合成，說明結締組織生長因子和抗壞血酸可促進肌腱幹細胞的成肌腱分化。被結締組織生長因子和抗壞血酸誘導兩周後，肌腱幹細胞可形成了細胞膜樣結構，將這種細胞膜纏繞在迴紋針上，構建成肌腱樣組織，其具有相對疏鬆的細胞外基質和雜亂排列其中的肌腱幹細胞，以及表達Tenomodulin，I型膠原和III型膠原。將該肌腱樣組織移植到裸鼠體內8周和12周可形成新生肌腱組織，梭形細胞縱行分佈在平行的膠原纖維之間，並表達Tenomodulin，I型膠原和III型膠原蛋白。在大鼠髕腱損傷動物模型中，與對照組相比較，該肌腱樣組織可通過恢復肌腱組織結構及生物力學特性來促進肌腱癒合。 / 總的來說，本研究證實肌腱幹細胞可作為一種新的幹細胞來源用於肌腱組織工程促進肌腱再生。結締組織生長因子和抗壞血酸可調控肌腱幹細胞的成肌腱分化，並形成細胞膜結構。該細胞膜結構可在體外構建出不含外源性支架的肌腱樣組織，進而在裸鼠體內形成新生肌腱，並且在大鼠髕腱損傷模型中可有效的促進損傷肌腱的癒合。這種不含外源性支架的肌腱樣組織有希望成為肌腱組織工程技術的新手段，在肌腱再生和肌腱修復的臨床應用及基礎研究方面有廣泛的前景。 / Tendon injuries are common and tendon healing outcome is poor, because tendon contains few cells with limited capacities for self-repair/regeneration. The current treatments on tendon injuries including drugs, physiotherapy, and surgery are not ideal and there is a need for the development of novel tissue-engineering strategies for tendon repair. / Previous studies have shown positive effects of bone marrow-derived mesenchymal stem cells (BMSCs), dermal fibroblast, tenocytes, and embryonic stem cells-derived MSCs for tendon repair/regeneration. However, these cells have limitations including insufficient differentiation; risk of teratoma and ectopic bone formation etc. Recently, stem cells have been isolated from tendons of human, mouse, rat and rabbit and considered as a new alternative cell source for tendon tissue engineering (TDSCs). For tenogenic differention of MSCs, connective tissue growth factor (CTGF) and ascorbic acid (one form of vitamin C) are reported to play important roles in promoting collagen and other extracellular matrixes (ECM) production, and regulating the MSCs differentiation towards tenogenic pathway. / The aims of the current study are: (1) To investigate the use of TDSCs in tendon repair in a rat acute patellar tendon injury model; (2) To test the effects of CTGF and ascorbic acid on tenogenic differentiation of TDSCs in vitro; (3) To construct scaffold-free tendon-like tissues in vitro using tenogenically differentiated TDSCs; (4) To promote tendon healing by engineered tendon-like tissues in a rat acute patellar tendon injury model. / In the rat acute patellar tendon injury model, in contract to control group, TDSCs treated group showed better alignment of collagen fibers and the significantly higher ultimate stress and Young’s modulus, indicating TDSCs may be an alternative cell source for tendon repair. The effects of CTGF and ascorbic acid on tenogenic differentiation of TDSCs were also confirmed with higher expression of tendon related markers such as Tenomodulin, Scleraxis, Thbs4, Type I Collagen, etc; with higher production of collagenous proteins. After treatment with CTGF and ascorbic acid for 2 weeks, TDSCs can form cell sheets, which can be harvested, rolled up on a U-shaped spring to form tendon-like tissues in culture, which had loose extracellular matrices and randomly distributed TDSCs and also expressed Tenomodulin, Type I & III collagen. Following transplantation of the engineered tendon-like tissue in nude mice for 8 and 12 weeks, neo-tendon tissues were formed, with thin and parallel collagen fibrils and extracellular matrices of Tenomodulin, Type I & III collagen. Finally in the rat patellar tendon window injury model, data suggested that the engineered tendon-like tissue could promote tendon healing with significantly improved histological features and biomechanical properties comparing to the control group. / In conclusion, our study has indicated that TDSCs can be an alternative cell source in tendon tissue engineering for tendon regeneration. The tenogenic differentiation of TDSCs, induced by CTGF and ascorbic acid in vitro, produces cell sheets, which can be constructed tendon-like tissues in vitro; to form neo-tendon and repair tendon injuries in vivo. The use of engineered scaffold-free tendon tissue for tendon tissue engineering has potentials in clinical application for tendon repair/regeneration. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Ni, Ming. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 107-126). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / DEDICATION --- p.I / ACKNOWLEDGEMENT --- p.II-III / TABLE OF CONTENTS --- p.IV-IX / PUBLICATIONS --- p.X-XII / ABBREVIATION --- p.XIII-XV / ABSTRACT (ENGLISH) --- p.XVI-XVIII / ABSTRACT (CHINESE) --- p.XIX-XX / Chapter CHAPTER 1 --- Introduction --- p.1 / Chapter 1.1 --- Epidemiology of tendon injury --- p.1 / Chapter 1.2 --- Healing process of tendon injury --- p.1 / Chapter 1.3 --- Tendon tissue engineering for tendon repair --- p.2 / Chapter 1.4 --- Stem cells in tendon repair --- p.2 / Chapter 1.5 --- Tenogenic differentiation of tendon derived stem cells --- p.7 / Chapter 1.6 --- Growth factors for tenogenic differentiation --- p.8 / Chapter 1.7 --- Vitamin C for tenogenic differentiation --- p.9 / Chapter 1.8 --- Summary --- p.10 / Chapter CHAPTER 2 --- Hypothesis, Objectives and Study Design --- p.11 / Chapter 2.1 --- Hypothesis --- p.11 / Chapter 2.1.1 --- Overall hypothesis --- p.11 / Chapter 2.1.2 --- Specific hypothesis --- p.11 / Chapter 2.2 --- Objectives --- p.12 / Chapter 2.3 --- Study design --- p.12 / Chapter 2.3.1 --- Study I --- p.12 / Chapter 2.3.2 --- Study II --- p.14 / Chapter 2.3.3 --- Study III --- p.14 / Chapter 2.3.4 --- Study IV --- p.17 / Chapter CHAPTER 3 --- Tendon-derived Stem Cells (TDSCs): A New Cell Source for Tendon Repair (Study I) --- p.19 / Chapter 3.1 --- Materials and Methods --- p.19 / Chapter 3.1.1 --- Isolation and characterization of rat GFP-TDSCs --- p.19 / Chapter 3.1.2 --- Animal surgery --- p.20 / Chapter 3.1.3 --- Ultrasound imaging --- p.25 / Chapter 3.1.4 --- Histology --- p.27 / Chapter 3.1.5 --- Biomechanical test --- p.27 / Chapter 3.1.6 --- Ex vivo fluorescence imaging --- p.28 / Chapter 3.1.7 --- Data analysis --- p.29 / Chapter 3.2 --- Results --- p.29 / Chapter 3.2.1 --- Gross observation of the injured knee and patellar tendon --- p.29 / Chapter 3.2.2 --- Histology of regenerated tendon tissue --- p.30 / Chapter 3.2.3 --- Biomechanical test of regenerated tendon tissue --- p.32 / Chapter 3.2.4 --- Ex vivo fluorescence imaging of GFP-TDSCs --- p.33 / Chapter 3.2.5 --- Ultrasound imaging of wound gap volume --- p.34 / Chapter 3.3 --- Discussion --- p.35 / Chapter 3.4 --- Conclusion --- p.50 / Chapter CHAPTER 4 --- Tenogenic Differentiation of Tendon-derived Stem Cells (TDSCs) (Study II) --- p.51 / Chapter 4.1 --- Materials and Methods --- p.51 / Chapter 4.1.1 --- Tenogenic differentiation of tendon-derived stem cells (TDSCs) --- p.51 / Chapter 4.1.2 --- Quantification of collagenous proteins --- p.51 / Chapter 4.1.3 --- Quantitative Real Time PCR (qRT-PCR) --- p.52 / Chapter 4.1.4 --- Data analysis --- p.54 / Chapter 4.2 --- Results --- p.55 / Chapter 4.2.1 --- Quantification of collagenous proteins --- p.55 / Chapter 4.2.2 --- Tenogenic, osteogenic and chondrogenic markers mRNA expression --- p.57 / Chapter 4.2.3 --- Tendon extracellular matrix markers mRNA expression --- p.57 / Chapter 4.3 --- Discussion --- p.59 / Chapter 4.4 --- Conclusion --- p.66 / Chapter CHAPTER 5 --- Engineered Scaffold-free Tendon Tissue Produced by Tendon-derived Stem Cells (TDSCs) Cell Sheet (Study III) --- p.67 / Chapter 5.1 --- Materials and Methods --- p.67 / Chapter 5.1.1 --- In vitro engineered scaffold-free tendon tissue by TDSCs cell sheet --- p.67 / Chapter 5.1.2 --- In vivo neo-tendon formation using engineered scaffold-free tendon tissue in nude mouse model --- p.67 / Chapter 5.1.3 --- Histology and immunohistochemistry staining --- p.68 / Chapter 5.1.4 --- In vivo fluorescence imaging --- p.69 / Chapter 5.1.5 --- Data analysis --- p.70 / Chapter 5.2 --- Results --- p.70 / Chapter 5.2.1 --- Gross observation of TDSCs cell sheet and engineered scaffold-free tendon tissue --- p.70 / Chapter 5.2.2 --- Histological and immunohistochemical characteristics in engineered scaffold-free tendon tissue --- p.71 / Chapter 5.2.3 --- Gross observation and in vivo fluorescence imaging of neo-tendon tissue --- p.74 / Chapter 5.2.4 --- Histology of neo-tendon tissue --- p.75 / Chapter 5.2.5 --- Immunohistochemistry staining in neo-tendon tissue --- p.76 / Chapter 5.3 --- Discussion --- p.78 / Chapter 5.4 --- Conclusion --- p.82 / Chapter CHAPTER 6 --- Use of Engineered Scaffold-free Tendon Tissue for Tendon Repair (Study IV) --- p.83 / Chapter 6.1 --- Materials and methods --- p.83 / Chapter 6.1.1 --- Animal surgery --- p.83 / Chapter 6.1.2 --- Ex vivo fluorescence imaging --- p.84 / Chapter 6.1.3 --- Histology and immunohistochemistry staining --- p.85 / Chapter 6.1.4 --- Biomechanical test --- p.86 / Chapter 6.1.5 --- Ultrasound imaging --- p.87 / Chapter 6.1.6 --- Data Analysis --- p.87 / Chapter 6.2 --- Results --- p.88 / Chapter 6.2.1 --- Gross observation of the injured knee and patellar tendon --- p.88 / Chapter 6.2.2 --- Histology of regenerated tendon tissue --- p.89 / Chapter 6.2.3 --- Tendon specific and ECM markers expression in regenerated tendon tissue --- p.91 / Chapter 6.2.4 --- Osteogenic and chondrogenic specific markers expression in neo-tendon tissue --- p.93 / Chapter 6.2.5 --- The fate of the transplanted engineered scaffold-free tendon tissue --- p.93 / Chapter 6.2.6 --- Biomechanical test of regenerated tendon tissues --- p.94 / Chapter 6.3 --- Discussion --- p.96 / Chapter 6.4 --- Conclusion --- p.102 / Chapter CHAPTER 7 --- General Conclusions --- p.103 / Chapter 7.1 --- General discussion --- p.103 / Chapter 7.2 --- General conclusions --- p.105 / FUNDING --- p.106 / REFERENCES --- p.107 / APPENDIX --- p.127

"Recent data show that 7.6 million Americans have survived a myocardial infarction (MI), and 5.1 million Americans suffer from severe heart failure. Stem cell therapy has the potential to improve cardiac function after MI. Two promising cells for cardiovascular regeneration therapies include human mesenchymal stem cells (hMSCs) and pluripotent stem cell derived cardiomyocytes (hPS-CM) each with their own unique method for improving cardiac function post-infarct. However, a limiting factor to cell therapies is that the methods currently used to deliver cells to the myocardium, including intramyocardial injection (considered the gold standard), suffer from low retention rates. To promote localization of delivered cells to the infarct and increase retention rates, our lab has developed a fibrin biological suture that can deliver human mesenchymal stem cells (hMSCs) with an efficiency of 64% compared to just 11% with intramyocardial injection in the normal rat heart. In this dissertation we sought to examine the functionality of hMSC and hPS-CM seeded sutures and their impact on cardiovascular regeneration applications. We began by delivering hMSC seeded fibrin sutures to an infarcted rat heart and found that the sutures are an effective method to deliver cells to the infarcted myocardium and demonstrated a trend towards improved regional mechanical function in the infarct region over infarct alone. Next, we transitioned to using hPS-CM and developed methods to seed the sutures, as well as a method to measure hPS-CM contractility with high spatial and temporal resolution, while concurrently capturing calcium transients. This technique allowed us to examine the contractile behavior in terms of contractile strain and conduction velocity of hPS-CM seeded on fibrin microthreads over 21 days in culture. We found that the fibrin microthread is a suitable scaffold for hPS-CM attachment and contraction and that extended culture promotes cell alignment along the length of the suture as well as improvements in contractile function in terms of increases in contractile strain and conduction velocity. Finally, we delivered the hPS-CM seeded microthreads to an uninjured rat heart and found a delivery efficiency of 67%. Overall, we further demonstrated the technology of the fibrin suture to deliver cells to an infarct as well as the ability to support the attachment, contraction and delivery of hPS-CM to cardiac tissue. "

Current usage of human embryonic stem cells (hES) and induced pluripotent stem cells (iPS) in clinical therapies and personalized medicine are limited as a result of ethical, technical and medical problems that arise from isolation and generation of these cells. Isolation of hES cells faces ethical problems associated with their derivation from human pre-implantation embryos. The most controversial aspect of hES cell isolation targets the generation of autologous hES cell lines which requires the transfer of a somatic-cell nucleus from the patient to an enucleated oocyte. While already established embryonic stem cell lines from IVF embryos can be used in a similar manner, lack of genetic identity can cause therapy rejection from the host, and prevent their use in personalized medicine. Induced pluripotent stem cells on the other hand, are generated from somatic cells that have been reprogrammed in vitro to behave like stem cells. While these cells can potentially be used for personalized medicine without the risk of rejection by the host system, derivation methods prevent their therapeutic use. The most efficient method used to generate iPS cells involves usage of viral particles which can result in viral DNA being integrated in the host cell’s genome and render these cells non-compliant for clinical therapies. Other methods not involving viral particles exist as well, but the reprogramming efficiency is too low and technical problems with generating large enough numbers of cells prevent these methods from being feasible approaches for clinical therapies. Direct reprogramming of a differentiated cell into a developmentally more plastic cell would offer alternatives to applications in regenerative medicine that currently depend on either embryonic stem cells (ES), adult stem cells or iPS cells. We hypothesize that Xenopus laevis egg cytoplasmic extract contains critical factors needed for reprogramming that may allow for non-viral, chemically defined derivation of human induced pluripotent/multipotent cells which can be maintained by addition of exogenous FGF2. In this thesis we investigated a new method for generation of multipotent cells through determining the ability of select fractions of Xenopus laevis egg extract to induce multipotency in already differentiated cells. We were able to identify select fractions from the extract that in combination with exogenously added FGF2 can reprogram and maintain the reprogrammed cells in an undifferentiated state. The findings of this work also determined that Xenopus laevis egg extract mRNA is required for achieving full reprogramming. The body of work presented in this thesis showed the ability of FGF2 isoforms to bind and activate select FGF receptor tyrosine kinases, act as extracellular mitogenic factors to support growth of hES cells in an undifferentiated state as well bind to nuclear DNA and affect expression of endogenous genes. Moreover, we showed that all FGF2 isoforms can induce expression of stem cell specific proteins in human dermal fibroblasts as well as extend lifespan of human dermal fibroblasts in vitro. In this work we identified HECW1, the gene coding for E3 ubiquitin ligase NEDL1, as a novel nuclear target for all FGF2 isoforms and showed that overexpression of recombinant FGF2 isoforms in human dermal fibroblasts can down regulate expression of HECW1 gene.

"Human umbilical cord blood (CB) hematopoietic stem cells (HSCs) have well established applications for cellular therapy. Current protocols for isolating HSCs from bone marrow or cord select for CD34 + cells, however some CD34 - populations have recently been shown to also contain strong HSC activity. Thus the positive selection of HSCs based on cell surface markers remains controversial. However, it is clear from the literature that differentiated hematopoietic cells (lineage positive, Lin + ), representing the vast majority (>90%) of most blood populations, contain no long-term reconstitution potential. Thus Viacell Inc. (Worcester, MA) expands and enriches its populations of cells containing HSCs by removing only those Lin + cells known not to contain HSCs. This is accomplished on two separation columns (post-sep-1, and post-sep-2) (separated by 7 days of cell growth) that contain a variety of antibodies to known differentiation surface markers. Although this process strongly enriches functional HCSs, these primitive cell populations remain biochemically uncharacterized. Because HSC populations containing long chromosomal telomeres and high telomerase activity (which helps maintain telomeres) have been shown to display the strongest long-term reconstitution potential, the purpose of this thesis was to investigate these two parameters in selected samples of Viacell’s ex vivo amplification procedure. Two specific hypotheses were tested: 1. the removal of Lin + cells will appear to increase the telomerase activity and telomere lengths in the remaining cell population, and 2. these two parameters will decrease upon hematopoietic cell differentiation and proliferation. Telomerase activity was assayed using a telomeric repeat amplication protocol (TRAP), and normalized relative to a cancer cell line positive control. Relative to fresh cord blood, telomerase activity was found to increase significantly in post-sep-1 (from 8.5 ± 1.5% to 76.2 ± 4.9%, p = 0.0001, n = 5) and post-sep-2 (8.5 ± 1.5% to 111.3 ± 4.9%, p = 0.0001, n = 5) fractions following the removal of Lin + cells. This increase was found to be highly reproducible, showing very low intra-cord and inter-cord variability. Telomere lengths were assayed using a telomere length assay (TLA). Relative to fresh cord blood, telomere lengths increased significantly in post-sep-1 (from 10 to 12 kb, n = 2) and post-sep- 2 (from 10 to 14 kb, p = 0.001, n = 2) fractions. These apparent increases likely result from the direct removal of cells low in telomerase activity with short telomeres since the Lin + cells from the post-sep-1 column were found to contain relatively low telomerase activity (32.1 ± 15%, p = 0.001, n = 2) and short telomeres (7.5 kb, p = 0.001), which supports our first hypothesis. Finally, we show that telomerase activity and telomere lengths decreased in Day-14 cells (expanded and differentiated 14 days) relative to post-sep-2 (from 111.8 ± 19.6% to 54 ± 21.2%, p = 0.001, n = 3 for the TRAP, and from 14 kb to 9 kb, p = 0.0001, n = 2 for the TLA). Those two parameters also decreased in pre-sep-3 cells (terminally differentiated by treatment with All Trans Retinoic Acid for 14 days) relative to post-sep-2 (from 111.3 ± 4.9% to 14.8 ± 1.7%, p = 0.0001, n = 6 for the TRAP, and from 14 kb to 7.5 kb, p = 0.001 for the TLA), supporting our second hypothesis. Telomerase activity was found to not directly correlate with CD34 + CD38 - content, supporting recent observations that a significant portion of HSCs reside outside this population."

"Recent evidence suggests that delivering human mesenchymal stem cells (hMSCs) to the infarcted heart reduces infarct size and improves ventricular performance. However, cell delivery systems have critical limitations such as inefficient cell retention and poor survival, and lack targeted localization. Our laboratories have recently developed a method to produce discrete fibrin microthreads that can be attached to a needle and delivered to a precise location within the heart wall. We hypothesize that fibrin microthreads will support hMSC proliferation, survival and retention of multipotency, and may therefore facilitate targeted hMSC delivery to injured tissues such as infarcted myocardium. To test this hypothesis, we bundled 100 μm diameter microthreads to provide grooves to encourage initial cell attachment. We seeded hMSCs onto the microthread bundles by applying 50,000 cells in 100 μL of media. The number of cells adhered to the microthreads was determined up to 5 days in culture. Cell density on the fibrin microthreads increased over time in culture, achieving an average density of 730 ± 101 cells/mm2. A LIVE/DEAD assay confirmed that the cells were viable and Ki-67 staining verified the increase in cell number over time was due to proliferation. Additionally, functional differentiation assays proved that the hMSCs cultured on microthreads retained their ability to differentiate into adipocytes and osteocytes. The results of this study demonstrate that delivering 1 to 4 cell seeded microthread bundles to the infarcted rat myocardium has the potential to produce a positive improvement in mechanical function and these microthreads support hMSC proliferation and survival. Additionally these findings suggest that cell-seeded microthreads may serve a platform technology to improve localized delivery of viable cells to infarcted myocardium to promote functional tissue regeneration. "

The longstanding belief that women are born with a finite ovarian reserve has been debated for over a decade, ever since the discovery, and subsequent isolation, of purported oogonial stem cells (OSCs) from adult mammalian ovaries. This rare cell population has now been reported in the mouse, rat, pig, rhesus macaque monkey and humans and, although a physiological role for the cells has not been proven, they do appear to generate oocytes when cultured in specific environments, resulting in live offspring in rodents. The primary aim of this thesis was to verify independently the existence of OSCs in human ovary and determine whether they could be isolated from a large animal model, the cow. The secondary aim was to investigate the cells’ in vitro potential, both to undergo neo-oogenesis and as a model for germ cell development. Putative bovine and human OSCs were isolated from disaggregated adult ovarian cortex using a previously validated fluorescence-activated cell sorting (FACS)-based technique, with cells sorted for externally expressed DDX4 (VASA). Freshly isolated and cultured cells were characterised by analysing their expression of pluripotency and germline markers, using RT-PCR, immunocytochemistry and Western blotting. The in vitro neo-oogenesis potential of the cells was explored by injecting fluorescently labelled cells into fragments of adult ovarian cortex and by forming aggregated artificial “ovaries” with putative OSCs and fetal ovarian somatic cells. Germ cell model experiments comprised treatment of cultured cells with BMP4 and/or retinoic acid (RA), with subsequent quantitative RT-PCR and immunocytochemistry analysis for downstream BMP4- and RA-response genes, and liposomal-mediated transfection of cells with a DAZL overexpression plasmid to assess their meiosis-related gene response. Scarce populations of putative OSCs were retrieved from 5 human samples (aged 13- 40 years) and 6 bovine samples. The cells were cultured long-term for up to 7 months and demonstrated consistent expression of several pluripotency-associated and germline markers at the mRNA and protein level, including LIN28, NANOG, POU5F1 (OCT4), IFITM3 (fragilis), STELLA, PRDM1 (BLIMP1), and C-KIT, indicating their early germline nature. Investigation of neo-oogenesis potential revealed that putative human OSCs were associated rarely with fetal somatic cells in primordial follicle-like structures, but could not be confirmed to have undergone oogenesis. However, like early germ cells, putative bovine and human OSCs were BMP4 and RA responsive, with both species demonstrating significant upregulation of expression of ID1 and bovine cells exhibiting a significant increase in MSX1, MSX2 and the meiotic marker SYCP3 in response to BMP4 and/or RA treatment. Cells could be successfully transfected to overexpress DAZL; however, no significant downstream gene expression changes were observed. This is the first report of putative bovine OSC isolation and corroborates a previous report showing putative human OSC isolation. Although the expression of both stem cell and germline markers indicates the cells have characteristics of OSCs, their capacity to enter meiosis and form functional oocytes has yet to be determined. Putative bovine OSCs, however, show promise as a novel model for investigating germ cell development. If their potential can be harnessed, then OSCs may have a role in clinical applications, for example in fertility preservation, in the future. Future experiments will examine the neo-oogenesis capabilities of the cells further and explore novel cell delivery systems for clinical use.

惡性腫瘤嚴重威脅著人類的身體健康，其治療也成為人類關注的焦點。傳統的化學療法和放射療法由於缺乏特異性，取得療效的同時往往也帶來較大的毒副作用。隨著對腫瘤發生發展分子機制認識的不斷深入，腫瘤的基因治療已成為攻克和治愈腫瘤最具希望和挑戰的研究領域。近年來研究發現骨髓間充斥幹細胞(MSCs)可被募集至腫瘤或損傷部位并參與腫瘤生長或組織修復，研究證明間充斥幹細胞通過靜脈注入帶瘤鼠（比如乳腺癌、膠質瘤、結腸癌及黑色素瘤）體內后，特異性的分佈于生長中的腫瘤中。這種特異性向腫瘤組織趨化轉移的特性使得骨髓間充斥幹細胞成為腫瘤基因靶向治療的載體的理想細胞。酶蛋白基因如單純皰疹病毒胸苷激酶(HSV-TK)可以使一些無毒或低毒的前藥轉化為強細胞毒性物質，殺死腫瘤細胞。我們前期實驗結果表明，通過遺傳改造后的表達TK基因的MSCs在GCV的存在下，具有殺傷腫瘤細胞抑制腫瘤生長的能力。但沒有改造的MSCs遷移至腫瘤之後可能會分化成成纖維細胞或者腫瘤基質細胞等支持腫瘤生長，但其命運和影響到底如何，我們怎麼樣進一步促進其向腫瘤的遷移以提高殺傷腫瘤的效率是本研究需要解決的問題。 / 本研究擬採用免疫螢光組織化學技術和分子生物學等技術研究和觀察MSCs對腫瘤（以乳腺癌，前列腺癌為例）的趨化過程及其在腫瘤生長中的作用，在在此基礎上研究促進攜帶HSV-TK自殺基因的MSCs的腫瘤靶向性細胞治療策略，採用分子和細胞生物學等方法評估其對荷瘤鼠體內腫瘤殺傷的原理，為利用TK-MSCs腫瘤的靶向治療奠定基礎。 / 研究結果顯示體外共培養的條件下，小鼠骨髓間充斥幹細胞可促進小鼠乳腺癌細胞增長，且增長速度同培養體系中間充斥幹細胞數目呈正相關。將兩種細胞混合注射于裸鼠體內，相比共注射小鼠皮膚成纖維細胞，間充斥幹細胞可促進體內腫瘤生長。使用人胚胎骨髓間充斥幹細胞和前列腺癌細胞可得出類似的效果。將腫瘤組織切片分析發現間充斥幹細胞促進體內腫瘤細胞增殖的同時，提高了腫瘤組織內血管密度。體外實驗發現共培養前列腺癌細胞和間充斥幹細胞可促進血管生成且在間充斥細胞內同血管增生相關的蛋白表達量都有相應提高，進一步證實間充斥幹細胞可能通過促進血管增生從而促進腫瘤生長。另外，我們利用人胚胎來源的骨髓間充斥幹細胞建立了穩定表達TK自殺基因的細胞系，且在GCV的存在下具有抑制腫瘤生長的能力。為了促進它們向腫瘤遷移的能力，我們用多柔比星預處理腫瘤細胞，和沒處理過的對照組相比，能增強對表達TK的間充斥幹細胞的招募能力。且在聯合利用多柔比星和TK的條件下，腫瘤生長能得到較大程度的抑制，這種抑制作用强於單獨使用多柔比星和表達自殺基因的間充斥幹細胞系統。初步認為是多柔比星的處理能增強腫瘤組織內炎性介質的分泌從而增強間充斥幹細胞的遷移達到增強自殺基因系統殺死腫瘤細胞的目的。 / 總的來說，雖然間充質幹細胞對腫瘤的生長存在一定的促進作用，但我們仍能對其進行遺傳改造，且在其它抗腫瘤藥的配合下達到最大的抗腫瘤效果。 / Eradication of cancer, especially when it has metastasized is extremely difficult and conventional cancer therapies are simply unable to specifically target tumors/cancers, thus causing unwanted side effects and complications. Recently, it has been shown that bone marrow mesenchymal stem cells (MSCs) are able to migrate specifically to tumors and contribute to the formation of tumor-associated stroma. These properties make MSCs good candidates as anti-tumor agent delivery vehicles and lead to a great deal of interest in the possibility of genetically modifying MSCs to express anticancer molecules and using them as specific targeted anticancer agents. We and others have showed that MSCs have the ability to migrate towards various cancer cells including breast, colon, fibrosarcoma and prostate cancer cells. Suicide gene therapy is widely used in cancer gene therapy. When stably infected with herpes simplex virus thymidine kinase gene by lentivirus, TK-MSCs maintained their MSCs characters and tumor tropism potential and significantly inhibited tumor growth, in the presence of the pro-drug ganciclovir (GCV). Improve MSCs homing to tumor tissue as anti-tumor gene therapy vehicles and maximizing their tumor killing effects is highly warranted. Furthermore, MSCs interact with tumor cells in numerous ways, which have the potential to support or suppress tumor growth. Therefore the fate and role of MSCs engrafted in tumor sites need to be clarified in order to making better use of these cells as anti-cancer agent delivery vehicles. / The aims of the current study are: (1) to study the role and fate of MSCs homed into the tumors; (2) to establish human bone marrow MSCs that stably express the TK genes; (3) to investigate the methods that enhance the anti-tumor efficiency of TK-MSCs. / In this study, bone marrow-derived mesenchymal stem cells from mice or human fetus were isolated and characterized. Effects of BM-MSCs on tumor cell proliferation in vitro were analyzed in a co-culture system with mouse breast cancer cell 4T1 cells. Both co-culture with BM-MSCs and treatment with MSC-conditioned medium led to enhanced growth of 4T1 cells. Co-injection of 4T1 cells and MSCs into nude mice led to increased tumor size compared with injection of 4T1 cells alone. Identical experiments using human prostate cancer cell DU145 cells and hBM-MSCs instead of 4T1 cells and mBM-MSCs yielded similar results. Compared with tumors induced by injection of cancer cells alone, tumor vessel area was greater in tumors from co-injection of 4T1 or DU145 with BM-MSCs, which correlated with decreased central tumor necrosis and increased tumor cell proliferation. Furthermore, both conditioned medium from co-cultures of hBM-MSCs and DU145 cells or hBM-MSCs alone was able to induce angiogenesis in human umbilical vein endothelial cells (HUVEC). When hBM-MSCs exposed to DU145 cells environment, the expression of markers associated with neovascularization (α-SMA, VEGF, TGF-β and IL6) were increased. Together, these results indicate that MSCs promote tumor growth both in vitro and in vivo and suggest that tumor promotion in vivo may be attributable in part to enhanced angiogenesis. / Immortalized human fetal bone marrow-derived MSCs (hfBMSCs) expressing herpes simplex virus thymidie kinase was established by conventional lentiviral transduction method. Functional expression of TK was evaluated by cytotoxicity in the presence of its prodrug GCV. SV40-TK-hfBMSCs exhibited comparable proliferation, surface phenotype expression, multi-differentiation potential and tumor-tropic migration ability as hfBMSCs. By measurement of tumor volume, repeated injection of the SV40-TK-hfBMSCs and subsequent consecutive GCV administration could suppress tumor growth in DU145 or PC3 human prostate tumor xenograft nude mice model without causing weight loss. However, its clinical applications are still limited. Alternative strategies have been pursued in this study by the use of combination therapy with cytotoxic chemotherapy to improve the overall efficacy of the TK-hfBMSCs/GCV system. / TK-hfBMSCs/GCV was evaluated alone or combined with low-dose doxorubicin in human prostate carcinoma DU145 xenografts in nude mice, testing for effects on local growth and overall survival. Tissues were evaluated through immunofluorescence and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining (TUNEL) for treatment effects on tumor cell proliferation and apoptosis. Transwell migration assay was used to access the migration ability of TK-hfBMSCs to tumor cells upon doxorubicin treatment and caspase-3 activity was conducted for test the tumor cells apoptosis under TK-hfBMSCs/GCV, doxorubicine, or combination of the two compound treatments respectively. Only minimal growth inhibition was observed in DU145 after treatment with TK-hfBMSCs/GCV or doxorubicin alone at doses and time points as indicated. In contrast, the combination of both agents resulted in a significant growth inhibition. Caspase-3, plays a central role in the execution-phase of cell apoptosis, was increased by TK-hfBMSCs/GCV or doxorubicine and also to a much greater extent by the combination treatment. Treatment by TK-hfBMSCs/GCV resulted in only a slight decrease in tumor growth compared with controls. Treatment with low-dose doxorubicin alone resulted in a small, nonstatistically significant decrease in tumor growth; In contrast, combined low-dose doxorubicin and TK-hfBMSCs/GCV was markedly inhibitory compared with control, doxorubicin alone, or TK-hfBMSCs/GCV alone. During the whole treatment process, no significant weight loss was observed. Furthermore, combined therapy induced increased area of necrosis, significant apoptosis and decreased tumor cell proliferation in treated tumors. Taken together, low dosage of doxorubicin could be used in combination with TK-hfBMSCs based suicide gene therapy. / In conclusion, we have demonstrated that BM-MSCs could increase the growth of human prostate cancer and mouse breast cancer. The promotion effect may partly attribute to the increased expression of pro-angiogenic factors in BM-MSCs in tumor microenvironment and subsequent enhancement in angiogenesis and tumor growth. The current study also suggests combination of TK-hfBMSCs/GCV and doxorubicin was more effective in inhibiting prostate cancer cells growth than TK-hfBMSCs/GCV or doxorubicin alone. Although many problems need to be resolved for further application, our study provided the possibility of a new strategy of suicide gene-based therapy accompanied by low dosage of chemotherapy in treating prostate cancer. Therefore MSCs were described as a “double-edged sword in their interaction with tumors. However, if MSCs are suitably engineered with anticancer genes they could be employed as a valuable “single-edged sword“ against cancers. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhang, Ting. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 120-158). / Abstracts also in Chinese. / ACKNOWLEDGEMENT --- p.ii / PUBLICATIONS --- p.vii / ABSTRACT --- p.xiii / Chapter CHAPTER 1 --- Introduction --- p.1 / Chapter 1.1 --- Mesenchymal stem cells (MSCs) --- p.2 / Chapter 1.2 --- Tumor microenvironment and involvement of MSCs in tumor establishment --- p.5 / Chapter 1.3 --- Tumors-tropic characteristics of MSCs --- p.15 / Chapter 1.4 --- Impact of MSCs on in vivo tumors --- p.21 / Chapter 1.5 --- In vivo imaging demonstrating MSCs tumor-homing potentials --- p.25 / Chapter 1.6 --- Evidence for use of MSCs as anti-tumor agents delivery vehicles --- p.26 / Chapter 1.7 --- Homing strategies to enhance efficacy and safety of MSCs therapy --- p.32 / Chapter 1.8 --- Summary --- p.35 / Chapter CHAPTER 2 --- Hypotheses, Objectives and Study Design --- p.35 / Chapter 2.1 --- Hypothesis --- p.35 / Chapter 2.2 --- Objective --- p.36 / Chapter 2.3 --- Study design --- p.37 / Chapter CHAPTER 3 --- Bone Marrow-derived Mesenchymal Stem Cells Promote Growth and Angiogenesis of Breast and Prostate Tumors (Study I) --- p.40 / Chapter 3.1 --- Materials and Methods --- p.40 / Chapter 3.2 --- Results --- p.49 / Chapter 3.3 --- Discussion --- p.64 / Chapter 3.4 --- Conclusions --- p.67 / Chapter CHAPTER 4 --- Immortalized human fetal bone marrow-derived mesenchymal stem cell expressing anti-tumor suicide gene for anti-tumor therapy in vitro and in vivo (Study II) --- p.68 / Chapter 4.1 --- Materials and Methods --- p.68 / Chapter 4.2 --- Results --- p.73 / Chapter 4.3 --- Discussion --- p.85 / Chapter CHAPTER 5 --- Enhanced antitumor effects by combination therapy using mesenchymal stem cell expressing anti-tumor suicide gene and Doxorubicin in a xenograft mouse model (Study III) --- p.89 / Chapter 5.1 --- Materials and Methods --- p.89 / Chapter 5.2 --- Results --- p.97 / Chapter 5.3 --- Discussion --- p.111 / Chapter CHAPTER 6 --- General discussion and conclusions --- p.116 / Chapter 6.1 --- General discussion --- p.116 / Chapter 6.2 --- General conclusions --- p.119 / FUNDING --- p.120 / REFERENCE --- p.120