Lau, Yuen Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 156-163). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract in Chinese (摘要） --- p.iii / Acknowledgements --- p.iv / Table of content --- p.V / List of figures --- p.ix / List of tables --- p.xiii / List of abbreviations --- p.xiv / Chapter 1 --- INTRODUCTION --- p.Page / Chapter 1.1 --- Embryonic stem cells (ESCs) --- p.1 / Chapter 1.1.1 --- What are ESCs and the characteristics of ESCs --- p.1 / Chapter 1.1.2 --- Promising use of ESCs in drug development and regenerative medicine --- p.1 / Chapter 1.1.3 --- Maintenance of self-renewal and pluripotent properties of ESCs --- p.3 / Chapter 1.2 --- Cell cycle in ESCs --- p.5 / Chapter 1.2.1 --- Cell cycle --- p.5 / Chapter 1.2.2 --- Characteristics of cell cycle of ESCs --- p.6 / Chapter 1.3 --- Telomere --- p.8 / Chapter 1.3.1 --- Telomere structure and the telomeric proteins --- p.8 / Chapter 1.3.2 --- End replication problem --- p.10 / Chapter 1.3.3 --- Telomere dysfunction in cancer and cellular aging --- p.11 / Chapter 1.4 --- Telomerase --- p.12 / Chapter 1.4.1 --- Telomerase and stem cell characteristics --- p.13 / Chapter 1.4.1.1 --- Telomerase and cell proliferation --- p.13 / Chapter 1.4.1.2 --- Telomerase and stem cell differentiation --- p.14 / Chapter 1.4.2 --- Regulation of telomerase expression/ activity --- p.15 / Chapter 1.4.2.1 --- Regulation of telomerase at different levels --- p.15 / Chapter 1.4.2.2 --- Regulation of telomerase activity by cellular components in ESCs --- p.16 / Chapter 1.5 --- PinXl --- p.18 / Chapter 1.5.1 --- Expression of PinXl --- p.18 / Chapter 1.5.2 --- Effects of PinXl on the activities and the sub-cellular localization of telomerase --- p.19 / Chapter 1.5.3 --- Structure-function relationship of PinXl --- p.19 / Chapter 1.5.4 --- Effect of PinXl on the growth rate of normal and cancer cells --- p.21 / Chapter 1.5.5 --- Other functions of PinX 1 V --- p.22 / Chapter 1.5.6 --- Mouse homolog of PinXl and its function in mESCs --- p.23 / Chapter 1.6 --- Aims of this study --- p.24 / Chapter 2 --- METERIALS AND METHODS --- p.Page / Chapter 2.1 --- mESC culture and differentiation --- p.25 / Chapter 2.1.1 --- Cell line --- p.25 / Chapter 2.1.2 --- Irradiation of MEF --- p.25 / Chapter 2.1.3 --- mESC culture --- p.26 / Chapter 2.1.4 --- Differentiation of mESCs --- p.26 / Chapter 2.1.5 --- Establishment and' culture of feeder-free mESCs --- p.28 / Chapter 2.1.6 --- Culture of feeder-free mESCs --- p.28 / Chapter 2.2 --- Trypan Blue Exclusion Assay --- p.29 / Chapter 2.3 --- Sub-cloning --- p.29 / Chapter 2.3.1 --- Amplification of the insert gene by PCR --- p.29 / Chapter 2.3.2 --- Purification of PCR products --- p.31 / Chapter 2.3.3 --- Restriction enzyme digestion --- p.32 / Chapter 2.3.4 --- Ligation of digested insert and vector --- p.33 / Chapter 2.3.5 --- Transformation of ligation product into competent cells --- p.34 / Chapter 2.3.6 --- Confirmation of positive clone by colony PCR --- p.34 / Chapter 2.3.7 --- Small scale preparation of the recombinant plasmid DNA --- p.35 / Chapter 2.3.8 --- Confirmation of positive clone by restriction digestion --- p.36 / Chapter 2.3.9 --- DNA sequencing of the recombinant plasmid DNA --- p.36 / Chapter 2.3.10 --- Large scale preparation of the recombinant plasmid DNA --- p.37 / Chapter 2.4 --- Design of siRNA targeting mPinXl and mPinXlt --- p.38 / Chapter 2.5 --- Transient transfection --- p.38 / Chapter 2.6 --- Cloning of siRNA into shRNA insert in Lentiviral Vector pLVTHM --- p.39 / Chapter 2.7 --- Lentiviral vector-mediated gene transfer to mESCs --- p.42 / Chapter 2.7.1 --- Lentivirus packaging --- p.42 / Chapter 2.7.2 --- Checking of successful transduction by lentivirus in HEK cells --- p.43 / Chapter 2.7.3 --- Multiple transductions to mESCs --- p.43 / Chapter 2.7.4 --- Selection of positive clones --- p.44 / Chapter 2.7.5 --- Monoclonal establishment --- p.44 / Chapter 2.8 --- "Total RNA preparation, Reverse Transcription (RT) and Quantitative Polymerase Chain Reaction (qPCR)" --- p.45 / Chapter 2.9 --- Immunocytochemistry --- p.46 / Chapter 2.10 --- Western Blotting --- p.48 / Chapter 2.10.1 --- Total Protein Extraction vi --- p.48 / Chapter 2.10.2 --- Measurement of Protein Concentration --- p.48 / Chapter 2.10.3 --- SDS-PAGE and chemiluminescent detection --- p.49 / Chapter 2.11 --- Co-immunoprecipitation --- p.51 / Chapter 2.12 --- Telomere Repeat Amplification Protocol (TRAP) Assay --- p.52 / Chapter 2.13 --- Cell cycle analysis --- p.54 / Chapter 2.14 --- MTT assay --- p.54 / Chapter 2.15 --- Statistical analysis --- p.55 / Chapter 3 --- RESULTS --- p.Page / Chapter 3.1 --- mPinXlt was discovered in mESCs --- p.56 / Chapter 3.2 --- mPinXl and mPinXlt were expressed at transcriptional level in the inspected mouse tissues --- p.61 / Chapter 3.3 --- Expression of mPinXl and mPinXlt changed upon differentiation --- p.64 / Chapter 3.4 --- mPinXl and mPinXlt were both located in the nucleolus and the nucleoplasm in undifferentiated mESCs --- p.69 / Chapter 3.5 --- Co-immunoprecipitation (Co-IP) of mPinXl and mPinXlt with mTERT --- p.73 / Chapter 3.6 --- Transient knockdown of mPinXl in mESCs --- p.78 / Chapter 3.6.1 --- Knockdown of mPinXl decreased proliferation but did not change cell viability --- p.79 / Chapter 3.6.2 --- Knockdown of mPinXl decreased telomerase activity --- p.79 / Chapter 3.6.3 --- Knockdown of mPinXl did not change pluripotency --- p.80 / Chapter 3.6.4 --- Knockdown of mPinXl did not affect cell cycle progression --- p.80 / Chapter 3.7 --- Transient knockdown of mPinXlt using siRNA against mPinXlt in mESCs --- p.88 / Chapter 3.8 --- Transient over-expression of mPinXl and mPinXlt in mESCs --- p.90 / Chapter 3.8.1 --- Over-expression of mPinXl and mPinXlt decreased cell proliferation but didn't affect cell viability --- p.91 / Chapter 3.8.2 --- Over-expression of mPinXl increased telomerase activity --- p.92 / Chapter 3.8.3 --- Over-expression of mPinXl and mPinXlt did not affect pluripotency --- p.93 / Chapter 3.8.4 --- Over-expression of mPinXl and mPinXlt did not affect cell cycle progression --- p.93 / Chapter 3.9 --- Stable over-expression and knockdown of mPinXl and mPinXlt in mESCs --- p.103 / Chapter 3.9.1 --- Expression of mPinXl and mPinXlt at mRNA and protein levels in all over-expression stable cell lines --- p.108 / Chapter 3.9.2 --- Expression of mPinXl and mPinXlt at mRNA and protein levels in mPinXl knockdown stable cell lines --- p.113 / Chapter 3.9.3 --- Proliferation of all stable cell lines --- p.116 / Chapter 3.9.4 --- Telomerase activity of all stable cell lines --- p.121 / Chapter 3.9.5 --- Cell cycle distribution of all stable cell lines --- p.123 / Chapter 3.9.6 --- Pluripotency of all stable cell lines --- p.127 / Chapter 3.9.7 --- Differentiation of the stable cell lines --- p.130 / Chapter 3.9.7.1 --- Size of EBs formed from stable cell lines at Day 7 --- p.130 / Chapter 3.9.7.2 --- Beating curves of the stable cell lines derived EBs --- p.130 / Chapter 4 --- DISCUSSIONS --- p.Page / Chapter 4.1 --- mPinXlt gene was detected in mESCs --- p.137 / Chapter 4.2 --- "Presence of mPinXl and mPinXlt in mouse tissues, mESCs and their differentiation derivatives" --- p.138 / Chapter 4.3 --- Differences in expressions of mPinXl and mPinXlt in undifferentiated mESCs and their differentiation derivatives --- p.139 / Chapter 4.4 --- mPinXl and mPinXlt are pre-dominantly localized in the nucleolus --- p.141 / Chapter 4.5 --- mPinXl and mPinXlt interacted with mTERT --- p.143 / Chapter 4.6 --- "Transient knockdown of mPinXl slightly inhibited, while over-expression of mPinXl slightly promoted telomerase activity" --- p.143 / Chapter 4.7 --- Both transient knockdown and over-expression of mPinXl inhibited the growth of mESCs --- p.146 / Chapter 4.8 --- Both stable knockdown and over-expression of mPinXl did not affect cell proliferation and telomerase activity of mESCs --- p.148 / Chapter 4.9 --- Involvement of mPinXl and mPinXlt in the differentiation process of mESCs --- p.149 / Chapter 4.10 --- Regulation of mPinXl gene expression by mPinXlt --- p.151 / Chapter 4.11 --- Future perspectives --- p.152 / Chapter 5 --- CONCLUSION --- p.154 / Chapter 6 --- REFERENCES --- p.156

Insulin-like growth factor-1 (IGF-1) is essential for oligodendrocyte (OL) development, promoting their survival, proliferation and differentiation. Furthermore, IGF-1 null mutant mice have a decrease in CNS myelination and in the number of OL progenitors (OLPs). IGF-1 interacts with the Type I IGF receptor to activate two main downstream signalling pathways, the PI3K/Akt and the Ras-Raf-MEK/ERK cascades, which mediate survival or proliferation of OLPs. The objective of this study is to elucidate the transduction pathways involved in IGF-I-stimulated protein synthesis, important for growth and differentiation of OLs. In other cellular systems, the PI3K/Akt pathway is involved in protein translation. mTOR and the p70 S6 kinase are downstream effectors that phosphorylate translation initiation factors (e.g. eIF-4E) and their regulators (e.g. 4E-BP1). OLPs were obtained from primary cultures and were treated with IGF-1 with or without inhibitors LY294002 or wortmannin (PI3K), rapamycin (mTOR), Akt III or IV, an adenovirus with a dominant negative form of Akt or PD98059 (ERK). Protein synthesis was assessed by metabolic labeling with [35S]-methionine, and protein phosphorylation by Western blotting. Results from the former showed that IGF-1 stimulates protein synthesis in a dose-dependent manner. Moreover, IGF-1 increases protein synthesis in OLPs through PI3K, mTOR, Akt and ERK activation. Concordantly, Western blot analysis reveals that IGF-1 stimulates phosphorylation of Akt, mTOR, ERK, S6 and 4E-BP 1. Activation of S6 and inactivation of 4E-BP1 occur through phosphorylation and are required for protein synthesis to take place. These events are dependent on the upstream activation of PI3K, Akt and mTOR.

Indiana University-Purdue University Indianapolis (IUPUI) / Human cord blood (CB) derived circulating endothelial colony forming cells (ECFCs) display a hierarchy of clonogenic proliferative potential and possess de novo vessel forming ability upon implantation in immunodeficient mice. Since survival of ECFC post-implantation is a critical variable that limits in vivo vasculogenesis, we tested the hypothesis that activation of Notch signaling or co-implantation of ECFC with human platelet lysate (HPL) would enhance cultured ECFC vasculogenic abilities in vitro and in vivo. Co-implantation of ECFCs with Notch ligand Delta-like 1 (DL1) expressing OP9 stromal cells (OP9-DL1) decreased apoptosis of ECFC in vitro and increased vasculogenesis of ECFC in vivo. The co-culture of ECFC with HPL diminished apoptosis of ECFC by altering the expression of pro-survival molecules (pAkt, pBad and Bcl-xL) in vitro and increased vasculogenesis of human EC-derived vessels both in vitro and in vivo. Thus, activation of the Notch pathway by OP9-DL1 stromal cells or co-implantation of ECFC with HPL enhances vasculogenesis and augments blood vessel formation by diminishing apoptosis of the implanted ECFC. The results from this study will provide critical information for the development of a cell therapy for limb and organ re-vascularization that can be applied to recovery of ischemic tissues in human subjects.

No description available.

Tse, Chi Lok. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 116-131). / Abstracts in English and Chinese. / Declaration --- p.i / Abstract --- p.iii / Abstract in Chinese --- p.v / Acknowledgements --- p.vi / Table of Contents --- p.vii / List of Figures --- p.X / List of Tables --- p.xii / List of Abbreviations --- p.xiii / Chapter CHAPTER 1 --- General Introduction / Chapter 1.1 --- Regenerative Medicine --- p.1 / Chapter 1.2 --- Embryonic Stem Cells and Reprogramming --- p.3 / Chapter 1.3 --- Transdifferentiation --- p.6 / Chapter 1.4 --- The Cerebellum --- p.7 / Chapter 1.4.1 --- Functions of the cerebellum --- p.7 / Chapter 1.4.2 --- Structure and organization of the cerebellum --- p.8 / Chapter 1.4.3 --- Principle cellular components in the cerebellum --- p.12 / Chapter 1.4.3.1 --- Purkinje cells --- p.12 / Chapter 1.4.3.2 --- Granule cells --- p.12 / Chapter 1.4.3.3 --- Mossy fibres --- p.13 / Chapter 1.4.3.4 --- Climbing fibres --- p.13 / Chapter 1.4.3.5 --- Deep cerebellar nuclei --- p.13 / Chapter 1.4.3.6 --- Other cerebellar neurons --- p.14 / Chapter 1.4.3.7 --- Neuroglia of the cerebellum --- p.16 / Chapter 1.4.4 --- Circuitry of the cerebellum --- p.17 / Chapter 1.5 --- Development of the Cerebellum --- p.21 / Chapter 1.5.1 --- Anatomical changes during cerebellar development --- p.21 / Chapter 1.5.2 --- Molecular control of cerebellar development --- p.25 / Chapter 1.5.2.1 --- Specification of the cerebellar region --- p.25 / Chapter 1.5.2.2 --- Neurogenesis from the ventricular zone --- p.26 / Chapter 1.5.2.3 --- Neurogenesis from rhombic lip --- p.29 / Chapter 1.6 --- Scope of the Thesis --- p.33 / Chapter CHAPTER 2 --- Materials and General Methods / Chapter 2.1 --- Materials for Molecular Biological Work --- p.35 / Chapter 2.1.1 --- Enzymes --- p.35 / Chapter 2.1.2 --- Chemicals and others --- p.35 / Chapter 2.1.3 --- Plasmid vectors and plasmid --- p.36 / Chapter 2.1.4 --- Solutions and media --- p.36 / Chapter 2.2 --- Materials for Tissue/Cell Culture --- p.38 / Chapter 2.2.1 --- Chemicals --- p.38 / Chapter 2.2.2 --- Culture media and solutions --- p.38 / Chapter 2.2.3 --- Culture cells --- p.39 / Chapter 2.3 --- Animals --- p.40 / Chapter 2.4 --- Materials for Immunocytochemistry --- p.40 / Chapter 2.5 --- Oligonucleotide Primers --- p.41 / Chapter 2.6 --- RNA Extraction --- p.44 / Chapter 2.7 --- Generation of cDNA from mRNA --- p.44 / Chapter 2.8 --- Preparation of Recombinant Plasmid DNA --- p.45 / Chapter 2.8.1 --- Small scale preparation of DNA --- p.45 / Chapter 2.8.2 --- QLAGEN plasmid midiprep kit method --- p.46 / Chapter 2.9 --- Preparation of Specific DNA Fragment from Agarose Gel --- p.46 / Chapter 2.10 --- Subcloning of DNA Fragments --- p.47 / Chapter 2.10.1 --- Preparation of cloning vectors --- p.47 / Chapter 2.10.2 --- Subcloning of DNA fragment --- p.48 / Chapter 2.10.3 --- Transformation of DNA into competent cells --- p.48 / Chapter 2.11 --- Preparation of Competent Cells --- p.48 / Chapter CHAPTER 3 --- Generation and Characterization of Induced Neurons / Chapter 3.1 --- Introduction --- p.50 / Chapter 3.2 --- Experimental Procedures --- p.51 / Chapter 3.2.1 --- Construction of expression vector --- p.51 / Chapter 3.2.1.1 --- Preparation of insert DNA --- p.51 / Chapter 3.2.1.2 --- Construction of entry vector --- p.52 / Chapter 3.2.1.3 --- Construction of destination vector --- p.52 / Chapter 3.2.1.4 --- Construction of expression vector --- p.52 / Chapter 3.2.2 --- Generation of induced neural cells --- p.57 / Chapter 3.2.2.1 --- Culture of mouse embryonic fibroblasts (MEF) --- p.57 / Chapter 3.2.2.2 --- Production of expression vector containing retroviruses --- p.57 / Chapter 3.2.2.3 --- Transfection and induction of neural fate of MEF --- p.57 / Chapter 3.2.3 --- Immunocytochemcial analysis --- p.58 / Chapter 3.2.4 --- Efficiency calculation --- p.59 / Chapter 3.3 --- Results --- p.62 / Chapter 3.3.1 --- A screen for cerebellar Purkinje and granule cell fate-inducing factors --- p.62 / Chapter 3.3.2 --- Characterization of the induced neurons --- p.67 / Chapter 3.3.2.1 --- Granule cell induction --- p.67 / Chapter 3.3.2.2 --- Purkinje cell induction --- p.71 / Chapter 3.4 --- Discussion --- p.102 / Chapter 3.4.1 --- Roles of inducing factors in Purkinje cells and granule cells development --- p.102 / Chapter 3.4.2 --- Mechanism of neural transdifferentiation --- p.107 / Chapter CHAPTER 4 --- Future Directions / Chapter 4.1 --- Complete Induction of Purkinje Cell Fate --- p.111 / Chapter 4.2 --- Induced Neurons of Different Subtypes --- p.112 / Chapter 4.3 --- Mechanism of Transdifferentiation --- p.114 / Chapter 4.4 --- Transdifferentiation and Regenerative Medicine --- p.114 / Bibliography --- p.116

Fetal pancreatic tissues can be a promising source for pancreatic progenitor cells (PPCs). In this regard, we have successfully isolated and characterized a population of fetal PPCs from first trimester human fetal pancreas using a previously established basic protocol. Upon exposure to a cocktail of conventional growth factors, these PPCs are amenable to differentiate into insulin-secreting islet-like cell clusters (ICCs); however, these ICCs have yet to exert additional efforts to direct to glucose-responsive cells. To address this issue, we have proposed two novel morphogenic factors in the present study, namely PDZ-domain-containing 2 (PDZD2) and angiotensin II (Ang II), a physiologically active peptide of the renin-angiotensin system (RAS), that potentially promote the differentiation and maturation of PPCs/ICCs. / In light of these findings, we conclude that we have discovered two novel mechanisms, the PDZD2 and Ang II/AT2 receptor signaling pathways, in the regulation of the development of PPCs/ICCs, thus implying their novel roles during islet development in vivo. The present study provides a "proof-of-principle" that a local RAS is critically involved in governing islet cell development. This work may contribute to devising protocols for maturation of pancreatic progenitors for clinical islet transplantation. / Local RASs have been reported to regulate the differentiation of tissue progenitor cells. It has yet to be confirmed whether such systems exist and govern the PPC development. To address this issue, we herein provided evidence that expression of RAS components was highly regulated throughout PPC differentiation. Locally generated Ang II was found to maintain PPC growth and differentiation via mediation of the Ang II type 1 and type 2 (AT1 and AT 2) receptors. We found that the AT2, but not AT1, receptor was a key mediator of Ang II-induced upregulation of beta-cell transcription factors. Transplantation of AT2 receptor-depleted ICCs into immune-privileged diabetic mice failed to ameliorate hyperglycemia, implying that AT2 receptors are indispensable during ICC maturation in vivo. / PDZD2 and its secreted form (sPDZD2) have been found to express in our fetal PPCs. We first evaluated the potential role of sPDZD2 in stimulating PPC differentiation and established an optimal concentration for such stimulation. We found that 10-9 M sPDZD2 promoted PPC differentiation, as evidenced by the up-regulation of the pancreatic endocrine markers and C-peptide content in the ICCs. It enhanced their expression of the L-type voltage-gated calcium ion channel (Cav1.2) and conferred an ability to secrete insulin in response to membrane depolarization. Yet these ICCs remained glucose-unresponsive because of the minimal expression of GLUT-2. We thus attempted to study another potential morphogenic candidate, Ang II. / To further test whether a functional RAS is present and if so, whether it regulates islet development in vivo, we employed a mouse embryo model at different embryonic days and reported a stronger AT2 receptor expression during the 2nd developmental transition of pancreas development. AT2 receptor blockade from e8.0 resulted in abnormalities in fetal pancreatic development. Neonates from these mother mice displayed destructed pancreas/islet architecture, a hampered ability in glucose-stimulated insulin-secretion possibly attributed to a decreased ratio of beta-cell to alpha-cell, and an impaired glucose tolerance at 4-wk old. / Leung, Kwan Keung. / Adviser: Po Sing Leung. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 254-284). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Indiana University-Purdue University Indianapolis (IUPUI) / The aim of this current study was to determine if the exposure of human dental pulp stem cells (HDPSC) to the DynaMatrix membrane will result in an increased production of angiogenic cytokines that are critical for pulp/root regeneration. Angiogenesis cytokine arrays have been established as a viable method for assessing expression of cytokines.20 HDPSC were chosen as they are expected to be found in the apical papilla and the infected immature root canal system of teeth that current regenerative endodontic techniques are designed to treat.

No description available.