Zebrafish has emerged as an important vertebrate model for studying hematopoiesis and its genetic and chemical modifiers. The zebrafish embryos are unique in their optical transparency, ease of maintenance and high fecundity. They are also amendable to genetic and pharmacological perturbation at high throughput. As a result, the embryos are suitable for various experimental techniques and have a high efficiency in large-scale drug screening. Recently, zebrafish has also emerged as a model for the study of human disease. In this model organism, primitive hematopoiesis is transitory and it occurs in the intermediate cells mass and comprises primarily erythroid cells. Definitive hematopoiesis arises from the ventral wall of dorsal aorta and moves to the caudal hematopoietic tissues, thence the kidney, where life-long and multi-lineage differentiation occurs. The chemical screening platform comprises O-dianisidine staining for hemoglobin containing cells (erythroid) during primitive hematopoiesis. Positive hits were validated based on flow cytometry of dissociated transgenic Tg(gata1:GFP) embryos and whole-mount in-situ hybridization (WISH) for hematopoietic genes. Gene knock-down was conducted by morpholinos (MO) injected into zebrafish embryos at 1-4 cell stage and the effects on hematopoietic development evaluated by WISH and quantitative real-time PCR. Chemical screening of 74 compounds has been performed. These compounds were obtained from a chemical library comprising 879 compounds from NIH (National Institutes of Health) and pre-screened by their effects on cancer cell lines. Four compounds (Tin(IV), chlorotriphenyl [1-(4-ethoxyphenyl)- 3-cyanoureato]-hydrogen,triethylamine, Nogamycin, N,N-Dibenzyldaunorubicin hydrochloride and Allyl 2,3,4-tri-O-benzyl-6-O-(tert-butyldimethylsilyl)-α- D-gluco-Pyranoside) which significantly reduced O-dianisidine staining were identified of which one (Allyl 2,3,4-tri-O-benzyl-6-O-(tert-butyldimethylsilyl) -α-D-glucopyranoside was shown to reduce GFP+ population in Tg(gata1:GFP) population Another chemical (2-Propanol,1,1'-[(1-methylethylidene)bis(4, 1-phenyleneoxy)]bis[3-[(1,1,3,3-tetramethylbutyl)amino]-,dihydrochloride]) was shown to reduce c-myb (marker of definitive hematopoiesis) expression in the ventral wall of dorsal aorta. I also attempted gene knock in zebrafish embryos based on anti-sense morpholino microinjection. A gene encoding for arl4ab was examined, as it was shown to be expressed in hematopoietic tissue in zebrafish embryos but its function is entirely unknown. Knock-down of arl4ab significantly reduced c-myb and runx1 expression in the ventral wall of dorsal aorta and it can be reversed by co-injecting arl4ab mRNA. scl and gata1 expression as well as GFP expression in transgenic Tg(flk1:GFP) embryos that represented vascular development was unaffected. In summary, a zebrafish platform for the study of chemical and genetic modifiers was established. The results have provided important leads for further study into the mechanisms whereby these modifiers regulate hematopoiesis in the zebrafish embryos. / published_or_final_version / Medicine / Master / Master of Medical Sciences

Zebrafish has emerged as an important model for the study of embryonic hematopoiesis. It is a well-characterized model with numerous advantages. Large amount of embryos can be produced by a single pair of zebrafish and the optically transparent embryos allow direct visualization and manipulation of embryonic processes. Large-scale chemical screening using zebrafish embryos can be developed for robust screening of chemical libraries. The zebrafish hematopoiesis resembles that of mammals and occurs in two successive waves, primitive and definitive hematopoiesis. High-throughput read-outs are available to study the effects of different chemicals and genetic modifications on hematopoiesis. In first part of this study, an initial screening using O-dianisidine staining and whole-mount in-situ hybridization as read-out for chemicals that might perturb the regulation of hematopoiesis was conducted. Positive hit was further evaluated by flow cytometry of dissociated transgenic Tg(gata1:GFP) zebrafish embryos. A total of 50 compounds were screened from the "Mechanistic set" chemical libraries obtained from Developmental Therapeutics Program of the National Cancer Institute. One compound, "NSC 643834" was shown to reduce O-dianisidine staining at different concentrations tested. The second part of this study was performed to investigate the role of inca2 in zebrafish hematopoiesis. inca2 was found to be upregulated in chordin morphant zebrafish in which primitive hematopoiesis was expanded. The spatial expression of inca2 was examined by whole mount in-situ hybridization of embryos at different developmental stages. Furthermore the function of inca2 was investigated by gene knockdown using inca2 anti-sense morpholino. Primitive hematopoiesis was perturbed, suggesting that inca2 might play an important role in the regulation of this process. In conclusion, the present study demonstrated the distinct advantages and feasibility of using zebrafish as a platform of high throughput chemical screening and genetic manipulation. The result provided important ground to investigate the regulatory mechanisms of embryonic hematopoiesis. / published_or_final_version / Medicine / Master / Master of Research in Medicine

Chan Sin-Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 154-169). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.iv / Abstract (Chinese Version) --- p.vi / Contents --- p.viii / Abbreviations --- p.xiii / List of Figures and Tables --- p.xvi / Chapter Chapter One --- General Introduction / Chapter 1.1 --- Hematopoiesis --- p.1 / Chapter 1.1.1 --- Ontogeny of hematopoiesis --- p.1 / Chapter 1.1.2 --- Hiercharay of hematopoiesis --- p.2 / Chapter 1.2 --- Regulation of hematopoiesis --- p.5 / Chapter 1.2.1 --- Bone marrow stromal cell --- p.5 / Chapter 1.2.2 --- Hematopoietic growth factor --- p.6 / Chapter 1.2.3 --- Hematopoietic growth factor receptors and signal transduction --- p.10 / Chapter 1.2.4 --- Transcriptional regulation of myeloid cell development --- p.11 / Chapter 1.3 --- Deregulated hematopoiesis - Leukemia --- p.20 / Chapter 1.3.1 --- Classification of leukemia --- p.20 / Chapter 1.3.2 --- Molecular basis of leukemia --- p.20 / Chapter 1.4 --- Prostaglandin E2 induced WEHI-3B JCS and JCS-14 cell differentiation --- p.22 / Chapter 1.4.1 --- Induced leukemia cell differentiation --- p.22 / Chapter 1.4.2 --- Inducer of cell differentiation - Prostaglandin E2 --- p.22 / Chapter 1.4.3 --- WEHI-3B JCS and subline JCS-14 cells --- p.24 / Chapter 1.5 --- The aims of study --- p.26 / Chapter Chapter Two --- Identification of differentially expressed genes during PGE2-induced WEHI-3B JCS-14 cell differentiation / Chapter 2.1 --- Introduction --- p.27 / Chapter 2.1.1 --- Strategy for studying PGE2-induced JCS-14 cell differentiation --- p.28 / Chapter 2.1.2 --- Method for studying differential gene expression: Microarry Technology --- p.29 / Chapter 2.2 --- Materials --- p.32 / Chapter 2.2.1 --- Cell line --- p.32 / Chapter 2.2.2 --- AtlasT M Mouse cDNA Expression Array --- p.32 / Chapter 2.2.3 --- Chemicals --- p.32 / Chapter 2.2.4 --- Solutions and buffers --- p.33 / Chapter 2.2.5 --- Reagents --- p.34 / Chapter 2.3 --- Methods --- p.35 / Chapter 2.3.1 --- Morphological study of PGE2-induced JCS-14 cell differentiation --- p.35 / Chapter 2.3.2 --- Preparation of total RNA from PGE2-induced JCS-14 cells --- p.35 / Chapter 2.3.2.1 --- Preparation of cell lysates --- p.35 / Chapter 2.3.2.2 --- Isolation of total RNA --- p.35 / Chapter 2.3.3 --- Preparation of cDNA probes --- p.36 / Chapter 2.3.3.1 --- Probe synthesis from total RNA --- p.36 / Chapter 2.3.3.2 --- Purification of the labeled cDNA probes --- p.37 / Chapter 2.3.4 --- Hybridization cDNA probes to the Atlas Array and stringency wash --- p.37 / Chapter 2.4 --- Results --- p.39 / Chapter 2.4.1 --- Morphological changes in PGE2-treated JCS-14 cells --- p.39 / Chapter 2.4.2 --- Analysis of total RNA from PGE2-induced JCS-14 cells --- p.43 / Chapter 2.4.3 --- Hybridization of cDNA probes to AtlasT M cDNA Expression Array --- p.45 / Chapter 2.5 --- Discussion --- p.73 / Chapter 2.5.1 --- Morphological study of JCS-14 cell differentiation --- p.73 / Chapter 2.5.2 --- Differentiation commitment of JCS-14 cell under PGE2 induction --- p.73 / Chapter 2.5.3 --- Gene expression profile by microarray --- p.74 / Chapter 2.5.4 --- Gene expression profile of 5 hours PGE2-induced JCS-14 cells --- p.74 / Chapter 2.5.5 --- Further analysis of regulatory genes in PGE2-induced JCS-14 cell differentiation --- p.77 / Chapter Chapter Three --- Expression profile of identified genes in WEHI-3B JCS-14 and JCS cell differentiation / Chapter 3.1 --- Introduction --- p.79 / Chapter 3.1.1 --- Quantitation of mRNA by Real time RT-PCR --- p.80 / Chapter 3.1.2 --- Relative quantitation of gene expression --- p.83 / Chapter 3.2 --- Materials --- p.85 / Chapter 3.2.1 --- Cell lines --- p.85 / Chapter 3.2.2 --- SYBR® Green PCR core kit --- p.85 / Chapter 3.2.3 --- Chemicals --- p.85 / Chapter 3.2.4 --- Solutions and buffers --- p.86 / Chapter 3.2.5 --- Enzymes and nucleic acids --- p.86 / Chapter 3.3 --- Methods --- p.88 / Chapter 3.3.1 --- Preparation of total RNA from PGE2-induced JCS-14 and JCS cells --- p.88 / Chapter 3.3.1.1 --- Preparation of cell lysates --- p.88 / Chapter 3.3.1.2 --- Isolation of total RNA --- p.88 / Chapter 3.3.2 --- Reverse transcription (RT) --- p.88 / Chapter 3.3.3 --- Design of real-time PCR primers --- p.88 / Chapter 3.3.4 --- Determination of relative efficiency of target and reference amplification by validation experiment --- p.89 / Chapter 3.3.5 --- Confirmation of expression profile of identified genes in JCS-14 and JCS cells by comparative CT method in real-time PCR --- p.90 / Chapter 3.4 --- Results --- p.91 / Chapter 3.4.1 --- Analysis of total RNA from PGE2-induced JCS-14 and JCS cells --- p.91 / Chapter 3.4.2 --- Validation experiment of real-time PCR primers --- p.93 / Chapter 3.4.3 --- Expression profile of specific genes in JCS-14 and JCS cells by comparative CT method --- p.101 / Chapter 3.5 --- Discussion --- p.114 / Chapter 3.5.1 --- Study of gene expression profiles in JCS-14 and JCS cell differentiation --- p.114 / Chapter 3.5.2 --- Transcription analysis by real-time PCR --- p.114 / Chapter 3.5.3 --- Gene expression profiles during PGE2-induced JCS-14 and JCS cell differentiation --- p.115 / Chapter Chapter Four --- Inhibition of specific gene expression in WEHI-3B JCS-14 and JCS cells using antisense blocking technique / Chapter 4.1 --- Introduction --- p.121 / Chapter 4.1.1 --- Antisense technique --- p.122 / Chapter 4.1.2 --- Design of antisense oligonucleotides --- p.125 / Chapter 4.1.3 --- Transfer of oligonucleotides to cells --- p.128 / Chapter 4.2 --- Materials --- p.129 / Chapter 4.2.1 --- Cell lines --- p.129 / Chapter 4.2.2 --- Chemicals --- p.129 / Chapter 4.2.3 --- Reagents --- p.129 / Chapter 4.2.4 --- Solutions --- p.129 / Chapter 4.3 --- Methods --- p.131 / Chapter 4.3.1 --- Design of antisense oligonucleotides --- p.131 / Chapter 4.3.2 --- Transfection of oligonucleotides into cells --- p.134 / Chapter 4.3.3 --- Morphological study of PGE2-induced JCS-14 and JCS cells --- p.134 / Chapter 4.4 --- Results --- p.135 / Chapter 4.4.1 --- Effect of antisense oligonucleotides on JCS-14 cell differentiation --- p.135 / Chapter 4.4.2 --- Effect of antisense oligonucleotides on JCS cell differentiation --- p.136 / Chapter 4.5 --- Discussion --- p.146 / Chapter 4.5.1 --- Effects of antisense B-myb on JCS-14 and JCS cell differentiation --- p.146 / Chapter 4.5.2 --- Effects of antisense thyroid hormone receptor (c-erbA) and transcription terminator factor (TTF-1) on JCS-14 and JCS cell differentiation --- p.147 / Chapter Chapter Five --- General Discussion / Chapter 5.1 --- Introduction --- p.148 / Chapter 5.2 --- Differentiation program triggered by Prostaglandin E2 --- p.148 / Chapter 5.2.1 --- Lineage preference during differentiation --- p.148 / Chapter 5.2.2 --- Differentially expressed genes during PGE2-induced JCS-14 cell differentiation --- p.149 / Chapter 5.2.3 --- Expression patterns of the three differentially expressed genes in PGE2-induced JCS-14 and JCS cells --- p.149 / Chapter 5.2.4 --- Antisense blocking during differentiation --- p.151 / Chapter 5.3 --- Further studies --- p.152 / References --- p.154

Chiu Lai-Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 137-152). / Abstracts in English and Chinese. / Acknowledgement --- p.II / Abstract --- p.IV / Contents --- p.VIII / Abbreviations --- p.XIV / Chapter Chapter One --- General introduction / Chapter 1.1 --- Haemopoiesis --- p.1 / Chapter 1.1.1 --- Background --- p.1 / Chapter 1.1.2 --- Regulation --- p.2 / Chapter 1.1.2.1 --- Stromal cells --- p.2 / Chapter 1.1.2.2 --- Haemopoietic regulator --- p.3 / Chapter 1.1.2.3 --- Haemopoietic regulator receptors and signal transduction --- p.5 / Chapter 1.2 --- Disorder of haemopoiesis --- p.9 / Chapter 1.2.1 --- Causes --- p.9 / Chapter 1.2.2 --- Types of leukemia --- p.9 / Chapter 1.2.3 --- Treatment of leukemia --- p.10 / Chapter 1.3 --- Prostaglandins --- p.13 / Chapter 1.3.1 --- Introduction --- p.13 / Chapter 1.3.2 --- Types and biosynthesis --- p.14 / Chapter 1.3.3 --- Prostaglandin receptors --- p.15 / Chapter 1.3.4 --- Prostaglandins and cell differentiation --- p.17 / Chapter 1.3.4.1 --- PGD2 and cell differentiation --- p.19 / Chapter 1.3.4.2 --- PGE2 and cell differentiation --- p.20 / Chapter 1.3.4.3 --- PGJ2 and cell differentiation --- p.22 / Chapter 1.4 --- WEHI-3B JCS cells --- p.25 / Chapter 1.5 --- Aims of study --- p.27 / Chapter Chapter Two --- Roles of Prostaglandin D2，E2 and J2 in WEHI-3B JCS myeloid leukemia cell differentiation / Chapter 2.1 --- Introduction --- p.28 / Chapter 2.1.1 --- Morphological studies of JCS cells --- p.28 / Chapter 2.1.2 --- Methods in determining cell proliferation --- p.29 / Chapter 2.1.3 --- Methods in determining differentiated cells --- p.31 / Chapter 2.2 --- Materials --- p.33 / Chapter 2.2.1 --- Cell line --- p.33 / Chapter 2.2.2 --- Chemicals --- p.33 / Chapter 2.2.3 --- Solutions and buffers --- p.34 / Chapter 2.3 --- Methods --- p.36 / Chapter 2.3.1 --- Microscopic studies of the JCS cells --- p.36 / Chapter 2.3.1.1 --- Histochemical staining of JCS --- p.36 / Chapter 2.3.1.2 --- Transmission electronic microscopic --- p.36 / Chapter 2.3.2 --- [3H]-thymidine incorporation assay --- p.37 / Chapter 2.3.3 --- MTT assay --- p.37 / Chapter 2.4 --- Results --- p.38 / Chapter 2.4.1 --- Histochemical staining of JCS cells --- p.38 / Chapter 2.4.2 --- Electron microscopy --- p.40 / Chapter 2.4.3 --- "Effect of PGD2, E2 and J2 on JCS cells proliferation" --- p.44 / Chapter 2.4.4 --- "Effect of PGD2, E2 and J2 on JCS cells differentiation" --- p.48 / Chapter 2.5 --- Discussion --- p.53 / Chapter 2.5.1 --- Morphological differentiation of JCS cells --- p.53 / Chapter 2.5.2 --- The ultra-structures of JCS cells --- p.53 / Chapter 2.5.3 --- "Effect of PGD2, E2 and J2 on JCS cells proliferation" --- p.54 / Chapter 2.5.4 --- "Effect of PGD2, E2 and J2 on JCS cells differentiation" --- p.55 / Chapter Chapter Three --- Roles of Prostaglandin E2 in normal haemopoiesis and the detection of PGE2 receptors expression in JCS and bone marrow cells / Chapter 3.1 --- Introduction --- p.57 / Chapter 3.1.1 --- Colony assay --- p.57 / Chapter 3.1.2 --- The use of RT-PCR --- p.58 / Chapter 3.1.3 --- Prostaglandin E receptors --- p.59 / Chapter 3.2 --- Materials --- p.62 / Chapter 3.2.1 --- Bone marrow cells --- p.62 / Chapter 3.2.2 --- Cell line --- p.62 / Chapter 3.2.3 --- Chemicals --- p.62 / Chapter 3.2.4 --- Primers --- p.63 / Chapter 3.2.5 --- Solutions and buffers --- p.64 / Chapter 3.2.6 --- Enzymes and reagents --- p.65 / Chapter 3.3 --- Methods --- p.66 / Chapter 3.3.1 --- Titration of mouse IL-3 --- p.66 / Chapter 3.3.2 --- Determination of suitable IL-3 concentration for growth of bone marrow cells in colony assay --- p.66 / Chapter 3.3.2.1 --- Preparation of bone marrow cells --- p.66 / Chapter 3.3.2.2 --- Preparation of culture medium for colony assay --- p.67 / Chapter 3.3.3 --- Investigation of the effect of PGE2 on normal haemopoiesis by colony assay --- p.68 / Chapter 3.3.4 --- Detection of PGE2 receptors expression on JCS cells and bone marrow cells --- p.68 / Chapter 3.3.4.1 --- Preparation of cell lysates --- p.68 / Chapter 3.3.4.2 --- Preparation of total RNA of JCS cells and bone marrow cells --- p.68 / Chapter 3.3.4.3 --- RT-PCR --- p.69 / Chapter 3.4 --- Results --- p.71 / Chapter 3.4.1 --- Titration of mouse IL-3 --- p.71 / Chapter 3.4.2 --- Effect of mouse IL-3 on normal haemopoiesis --- p.73 / Chapter 3.4.3 --- Effect of PGE2 on mouse IL-3 driven normal bone marrow cell differentiation --- p.76 / Chapter 3.4.4 --- Analysis of total RNA prepared from uninduced JCS cells and bone marrow cells --- p.79 / Chapter 3.4.5 --- "Expression of gapdh in heart, liver, spleen, JCS and bone marrow cells" --- p.81 / Chapter 3.4.6 --- "Expression of PGE2 receptors in heart, liver, spleen, JCS and bone marrow cells" --- p.82 / Chapter 3.5 --- Discussion --- p.84 / Chapter 3.5.1 --- Effect of PGE2 on IL-3 driven normal bone marrow cells differentiation --- p.84 / Chapter 3.5.2 --- "Expression of PGE2 receptors in heart, liver, spleen, JCS and bone marrow cells" --- p.85 / Chapter Chapter Four --- Gene expression profile of JCS cells under 5 hours of PGE2 induction / Chapter 4.1 --- Introduction --- p.88 / Chapter 4.1.1 --- Review of methods studying differential gene expression --- p.88 / Chapter 4.1.2 --- The choice of method studying differential gene expression --- p.92 / Chapter 4.1.3 --- The microarray --- p.93 / Chapter 4.2 --- Materials --- p.95 / Chapter 4.2.1 --- Cell line --- p.95 / Chapter 4.2.2 --- Kits --- p.95 / Chapter 4.2.3 --- Chemicals --- p.95 / Chapter 4.2.4 --- Solutions and buffers --- p.96 / Chapter 4.2.5 --- Reagents --- p.97 / Chapter 4.3 --- Methods --- p.98 / Chapter 4.3.1 --- Preparation of total RNA from PGE2 induced JCS cells --- p.98 / Chapter 4.3.2 --- Preparation of cDNA probes --- p.98 / Chapter 4.3.2.1 --- Probe synthesis from total RNA --- p.98 / Chapter 4.3.2.2 --- Column chromatography --- p.99 / Chapter 4.3.3 --- Hybridizing cDNA probes to the Atlas Array --- p.99 / Chapter 4.4 --- Results --- p.101 / Chapter 4.4.1 --- Spectrophotometric analysis of total RNA after ethanol precipitation --- p.101 / Chapter 4.4.2 --- Hybridization of cDNA probes to Atlas Array --- p.102 / Chapter 4.5 --- Discussion --- p.121 / Chapter 4.5.1 --- Genes with increased expression --- p.121 / Chapter 4.5.2 --- Genes with decrease expression --- p.127 / Chapter 4.5.3 --- Study of gene expression profile by microarray --- p.128 / Chapter Chapter Five --- General discussion / Chapter 5.1 --- Introduction --- p.131 / Chapter 5.2 --- Roles of PGE2 in JCS cells differentiation --- p.131 / Chapter 5.3 --- Roles of PGE2 in normal haemopoiesis --- p.134 / Chapter 5.4 --- Further studies --- p.135 / References --- p.137