Wing Y. Chan. / "March 2000." / Thesis (M.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references. / 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. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Dendritic cells (DCs) comprise a distinct lineage of potent antigen-presenting mononuclear phagocytes that serve as both mediators of innate immune responses and key facilitators of the adaptive immune response. DCs play both immunogenic and tolerogenic roles through their dual ability to elicit pathogen-specific T cell immunity as well as induce regulatory T cell (Treg) responses to promote tolerance in the steady state. The aim of the work presented here is to examine the normal regulatory mechanisms of DC development and function, starting with the dissection of mechanisms behind an aberrantly activated developmental pathway, followed by the exploration of new mechanisms governed by two candidate transcription factors. The first chapter of the thesis focuses on the growth factor receptor Flt3, an essential regulator of normal DC development in both mice and humans, and concurrently one of the most commonly mutated proteins found in acute myeloid leukemia (AML). We investigated the effect of its most common activating mutation in AML, the Flt3 internal tandem duplication (Flt3-ITD), and found that this mutation caused a significant cell-intrinsic expansion of all DC populations. This effect was associated with an expansion of Tregs and the ability to dampen self-reactivity, with an inability to control autoimmunity in the absence of Tregs. Thus, we describe a potential mechanism by which leukemia can modulate T cell responses and support Treg expansion indirectly through DCs, which may compromise immunosurveillance and promote leukemogenesis. The subsequent chapters explore the basic molecular mechanisms of DC development by using Flt3 expression as a guide to uncover new candidates involved in the DC transcriptional program. We show that Myc family transcription factor, Mycl1, is largely dispensable for DC development and function, contrary to recent published findings that propose a role in proliferation and T cell priming. On the other hand, we find that conditional deletion of our second candidate gene, an Ets family transcription factor, has diverse effects on DC development, monocyte homeostasis, and cytokine production. Overall, our studies highlight an unexpected molecular link between DC development and leukemogenesis, and elucidate novel mechanisms controlling DC differentiation and function.

This report describes the use of small molecule probes in the modulation of brain chemistry with the ultimate goal of developing novel therapeutics for the treatment of mood disorders. With an increasing number of people suffering from depression, there is a need to explore more diverse mechanisms of these diseases to better understand their cause and therefore provide insight into their treatment. Chapter 1 serves as an introduction and describes the current understanding of depression mechanisms, as well as a history of antidepressant therapeutics. The chapter then goes on to discuss, in depth, the mechanisms of G Protein-Coupled Receptor (GPCR) function and the implications of biased signaling. There is also an introductory overview of basic pharmacological terms. The chapter finishes with a summary of current technology available to measure GPCR function, including those utilized in the rest of this report. The remainder of the report is broken up into two parts. In the first part, I will describe my work to understand the opioid receptor system in the context of mood disorders. In Chapter 2, the atypical antidepressant tianeptine is discovered to act through the mu-opioid receptor (MOR), and a biochemical exploration is reported including an exploration of its unique properties in the context of G protein-dependent and -independent signaling, as well as preliminary in vivo and structure activity relationship studies into the mechanism of action. In Chapter 3, I will describe the biological characterization of the Mitragyna speciosa alkaloids at the opioid receptors. In particular, the major alkaloids mitragynine and 7-OH mitragynine are found to be partial agonists at the MOR and antagonists at the kappa-opioid receptor (KOR) with apparent G protein bias. In Chapter 4, alkaloids inspired by those found in Tabernanthe iboga, such as ibogaine, are synthesized and characterized at the opioid receptors. Through a novel 12- hydroxy-oxaibogamine scaffold, opioid activity is uncovered that is greatly increased in comparison to the ibogaine metabolite noribogaine. Analogs tested have varying degrees of potency and efficacy at all three opioid receptors, and one analog in particular is found to be a selective G protein biased partial KOR agonist. In Chapter 5, I will conclude the opioid section by taking a critical examination of commonly used assays for measuring arrestin recruitment by dissecting assay components and analyzing what is necessary to determine accurate calculations of bias within a cellular system. The alleged G protein bias of KOR agonist dynorphin is studied at great length, and a discussion on the future of understanding ligand bias is presented. In the second part of this report, I move away from opioids and instead focus on the growth factor signaling system as a second approach to uncovering novel therapeutics for depression. In Chapter 6, I describe a second potential mechanism of action of the natural product ibogaine in the context of glial cell line-derived neurotrophic factor (GDNF) signaling. The deconstructed iboga analog XL-008 is studied that is a superior releaser of GDNF and potentiates the signaling of a second growth factor, fibroblast growth factor 2 (FGF2). In the final Chapter 7, I look to the FGF family, both receptor and growth factor, as a novel target for depression. In order to identify small molecule modulators of the FGF receptor 1 (FGFR1), cell- based assays are developed and validated in a pilot screen. The strength of these assays are assessed, and the initial results from a full high throughput screen are presented.

As a master regulator of the epithelial state, p63 is a family member of the well-known tumor suppressor p53. It has previously been connected to a cancer-associated process, epithelial-to-mesenchymal transition (EMT), and here we find that it can be regulated by oncogenes involved in breast tumorigenesis. Specifically, activated forms of PIK3CA and H-RAS are able to strongly repress expression of ∆Np63α, which is the major p63 isoform in epithelial cells. In mammary epithelial lines, this oncogene downregulation occurs at the transcriptional level, and complete repression occurs over the course of several days. As p63 is repressed, the cells undergo EMT and acquire the ability to invade individually through a 3D collagen matrix. Strikingly, even when p63 is suppressed but no oncogene action is present, these cells undergo a mesenchymal shift, suggesting the importance of this gene in maintaining the epithelial state. Furthermore, it is particularly interesting that p63 protein and RNA levels are often low in breast tumors. By connecting H-RAS and PIK3CA signaling to p63, it is hypothesized that such oncogene suppression could account for tumor progression in cases where p63 levels are low. Here, it is proposed that p63 acts in a tumor-suppressive manner, although it can be overcome by oncogenes leading to changes in differentiation state and migratory capability, therefore drastically affecting breast carcinogenesis.

Traditionally, cancer epidemiologists have investigated the causes of disease under the premise that patients with a certain site of disease can be treated as a single entity. Then risk factors associated with the disease are identified through case-control or cohort studies for the disease as a whole. However, with the rise of molecular and genomic profiling, in recent years biologic subtypes have increasingly been identified. Once subtypes are known, it is natural to ask the question of whether they share a common etiology, or in fact arise from distinct sets of risk factors, a concept known as etiologic heterogeneity. This dissertation seeks to evaluate methods for the study of etiologic heterogeneity in the context of cancer research and with a focus on methods for case-control studies. First, a number of existing regression-based methods for the study of etiologic heterogeneity in the context of pre-defined subtypes are compared using a data example and simulation studies. This work found that a standard polytomous logistic regression approach performs at least as well as more complex methods, and is easy to implement in standard software. Next, simulation studies investigate the statistical properties of an approach that combines the search for the most etiologically distinct subtype solution from high dimensional tumor marker data with estimation of risk factor effects. The method performs well when appropriate up-front selection of tumor markers is performed, even when there is confounding structure or high-dimensional noise. And finally, an application to a breast cancer case-control study demonstrates the usefulness of the novel clustering approach to identify a more risk heterogeneous class solution in breast cancer based on a panel of gene expression data and known risk factors.

by Ma Suk Ling. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 106-129). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Publications --- p.vi / Abbreviations --- p.vii / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter 1.1 --- Epidemiology of AD --- p.2 / Chapter 1.2 --- Clinical and pathological features of AD --- p.3 / Chapter 1.2.1 --- Clinical features of AD --- p.3 / Chapter 1.2.2. --- Pathological features of AD --- p.3 / Chapter 1.3 --- Diagnosis of AD --- p.4 / Chapter 1.4 --- Classification of AD --- p.5 / Chapter 1.5 --- Causes of AD --- p.5 / Chapter 1.6 --- Risk factors --- p.5 / Chapter 1.6.1 --- Age --- p.5 / Chapter 1.6.2 --- Family history --- p.6 / Chapter 1.6.3 --- Genetics --- p.6 / Chapter 1.6.3.1 --- Autosomal dominant mutations --- p.6 / Chapter 1.6.3.2 --- Genotypes of Apolipoprotein E --- p.6 / Chapter 1.6.4 --- Environmental factors --- p.7 / Chapter Chapter 2 --- Pathology in Alzheimer's disease --- p.8 / Chapter 2.1 --- Overview of Alzheimer's disease pathology --- p.8 / Chapter 2.2 --- Amyloid plaques --- p.8 / Chapter 2.2.1 --- Amyloid precursor protein --- p.8 / Chapter 2.2.2 --- Processing ofAPP --- p.9 / Chapter 2.2.3 --- Amyloid β (Aβ) --- p.12 / Chapter 2.2.4 --- APP mutations and AD --- p.12 / Chapter 2.3 --- Neurofibrillary tangles (NFT) --- p.15 / Chapter 2.3.1 --- Tau --- p.15 / Chapter 2.3.2 --- Tau mutation and neurodegeneration --- p.17 / Chapter 2.4 --- Hypotheses for AD pathology --- p.18 / Chapter 2.4.1 --- Amyloid cascade hypothesis --- p.18 / Chapter 2.4.2 --- Inflammatory hypothesis --- p.20 / Chapter 2.4.2.1 --- Microglia and astrocytes --- p.21 / Chapter 2.4.2.2 --- Inflammatory cytokines --- p.23 / Chapter 2.4.2.3 --- Inflammation and AD --- p.25 / Chapter 2.4.3 --- ApoE hypothesis --- p.27 / Chapter 2.4.3.1 --- Apolipoprotein E --- p.27 / Chapter 2.4.3.2 --- ApoE and AD --- p.28 / Chapter 2.5 --- Theory towards the pathology of AD --- p.30 / Chapter Chapter 3 --- ApoE genotyping --- p.32 / Chapter 3.1 --- Introduction --- p.32 / Chapter 3.2 --- Materials and methods --- p.32 / Chapter 3.2.1 --- Patients and control subjects --- p.32 / Chapter 3.2.2 --- Blood sampling --- p.33 / Chapter 3.2.3 --- DNA genotyping --- p.34 / Chapter 3.2.4 --- Statistical analysis --- p.35 / Chapter 3.3 --- Results --- p.35 / Chapter 3.. --- Discussion --- p.38 / Chapter Chapter 4 --- IL-1β polymorphism in relation to the risk of ADin Chinese --- p.39 / Chapter 4.1 --- Introduction --- p.39 / Chapter 4.2 --- Materials and methods --- p.44 / Chapter 4.2.1 --- Patients and control subjects --- p.44 / Chapter 4.2.2 --- Blood sampling --- p.44 / Chapter 4.2.3 --- DNA genotyping --- p.44 / Chapter 4.2.4 --- Statistical analysis --- p.48 / Chapter 4.3 --- Results --- p.48 / Chapter 4.4 --- Discussion --- p.53 / Chapter Chapter 5 --- TNFα polymorphism in relation to the risk of ADin Chinese --- p.63 / Chapter 5.1 --- Introduction --- p.63 / Chapter 5.2 --- Materials and methods --- p.66 / Chapter 5.2.1 --- Patients and control subjects --- p.66 / Chapter 5.2.2 --- Blood sampling --- p.66 / Chapter 5.2.3 --- DNA genotyping --- p.66 / Chapter 5.2.4 --- Haplotype determination --- p.70 / Chapter 5.2.5 --- Statistical analysis --- p.70 / Chapter 5.3 --- Results --- p.70 / Chapter 5.4 --- Discussion --- p.75 / Chapter Chapter 6 --- LRP8 polymorphism in relation to the risk of ADin Chinese --- p.81 / Chapter 6.1 --- Introduction --- p.81 / Chapter 6.2 --- Materials and methods --- p.87 / Chapter 6.2.1 --- Patients and control subjects --- p.87 / Chapter 6.2.2 --- Blood sampling --- p.87 / Chapter 6.2.3 --- DNA genotyping --- p.87 / Chapter 6.2.4 --- Statistical analysis --- p.89 / Chapter 6.3 --- Results --- p.91 / Chapter 6.4 --- Discussion --- p.98 / Chapter Chapter 7 --- Conclusions and prospects for future work --- p.102 / Chapter 7.1 --- Conclusion --- p.102 / Chapter 7.2 --- Prospects for future work --- p.105 / Reference --- p.106

Cathelicidin, a pleiotropic host defense peptide, has been shown to promote cutaneous wound repair and reaches high levels in the gastric mucosa during acute Helicobacter pylori-associated inflammation. The expression of cathelicidin, nevertheless, has also been found to be down-regulated in gastric hyperplastic polyps, tubular adenomas, and adenocarcinomas. We therefore hypothesized that cathelicidin might contribute to gastric ulcer healing and suppress gastric cancer growth. In this study, the role of this peptide in gastric tissue repair and carcinogenesis was investigated. / Collectively, this study demonstrates for the first time that cathelicidin can promote tissue repair and suppress cancer growth in stomachs by eliciting differential cellular signaling and responses in normal and cancerous gastric epithelial cells. These unique biological activities may open up a novel therapeutic avenue for the treatment of these diseases. / Concerning gastric carcinogenesis, the human cathelicidin LL-37 lowered gastric cancer cell proliferation and delayed G1-S transition in vitro and inhibited the growth of gastric cancer xenograft in vivo. Knockdown or induction of endogenous LL-37 by RNA interference or 1alpha,25-dihydroxylvitamin D3, respectively, increased or suppressed cell proliferation. In this connection, LL-37 increased bone morphogenetic protein (BMP) signaling, manifested as increases in BMP4 expression and the subsequent Smad1/5 phosphorylation and the induction of Smad6 and Smad7. Moreover, LL-37 increased the expression of p21Waf1/Cip1, whose induction was abolished by the knockdown of BMP receptor II. Knockdown of BMP receptor II or p21Waf1/Cip1 also abrogated the anti-mitogenic action of LL-37. The activation of BMP signaling by LL-37 was accompanied with the inhibition of chymotrypsin-like and caspase-like activity of proteasome. In this regard, proteasome inhibitor MG-132 mimicked the effect of LL-37 by increasing BMP4 mRNA expression and Smad1/5 phosphorylation. In addition, cyclin E 2 was down-regulated by LL-37 via a BMP-independent mechanism. Further analysis of clinical samples revealed that LL-37 and p21Waf1/Cip1 mRNA expression were both down-regulated in gastric cancer tissues and their expression were positively correlated. These findings indicate that LL-37 inhibits gastric cancer cell proliferation through activation of BMP signaling via a proteasome-dependent mechanism. / In relation to gastric ulcer healing, results revealed that ulcer induction in rats increased the expression of rat cathelicidin rCRAMP in the gastric mucosa. Further increase in expression of rCRAMP by local injection of rCRAMP-encoding plasmid promoted ulcer healing by enhancing cell proliferation and angiogenesis. rCRAMP directly stimulated proliferation of cultured rat gastric epithelial cells (RGM-1), which was abolished by inhibitors of matrix metalloproteinase (MMP), epidermal growth factor receptors (EGFR) tyrosine kinase, or mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase. rCRAMP also increased EGFR and ERK1/2 phosphorylation via an MMP-dependent mechanism. Knockdown of transforming growth factor alpha (TGFalpha), which is a ligand of EGFR, by small interfering RNA completely nullified the mitogenic signals evoked by rCRAMP in RGM-1 cells. These findings suggest that rCRAMP exhibits pro-healing activity in stomachs through TGFalpha-dependent transactivation of EGFR and its related signaling pathway to induce proliferation of gastric epithelial cells. / Wu, Ka Kei. / Adviser: Joseph J. Y. Sung. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0252. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 153-178). / 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. / Abstracts in English and Chinese.

Yang Jie. / "January, 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 204-250). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Dong Shumin. / "February 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 187-220). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

As the prevalence of atherosclerosis has risen to an alarming level throughout the world, this thesis investigated: (1) the effects of type 2 diabetes mellitus on the risk factors for atherosclerosis and the intima-media thickness (IMT) of the common carotid arteries (a surrogate marker for atherosclerosis), (2) the contribution of various risk factors to the IMT of the common carotid arteries and (3) the interrelationship between the risk factors. / Atherosclerosis is the process by which the inner lining of a large or medium artery is deposited with lipids, cellular waste and other substances. It reduces the vessel's elasticity, lumen size and blood flow. Atherosclerosis is the primary underlying mechanism leading to cardiovascular and cerebrovascular diseases, the second and third leading causes of death in Hong Kong. / Both traditional and emerging risk factors for atherosclerosis were studied: traditional risk factors include age, blood pressure, indices of glycaemia control (fasting glucose, insulin and haemoglobin-Alc), and fasting lipids, while the emerging risk factors include, abdominal fat volume (subcutaneous and visceral), inflammatory markers (interleukin-6 (IL-6), interleukin-8 (IL-8) and high sensitivity c-reactive protein (hsCRP)), adiponectin, stress hormones (24 hr urinary noradrenaline and adrenaline, and plasma cortisol), and occupational stress (measured by a effort-reward imbalance questionnaire). / Starting with 204 subjects recruited from three different studies, data from 84 normoglycaemic subjects, 23 patients with impaired glucose tolerance (IGT) and 77 patients with diabetes mellitus (DM) were included in the analysis. When the IMT of the common carotid arteries and various risk factors were compared between normoglycaemic, IGT and DM subjects: (1) the IMT of the common carotid arteries showed an increasing trend with the worsening of glycaemia control (normal<IGT<DM), (2) increased prevalence of hypertension, dyslipidaemia, and obesity were observed among DM patients, and (3) increased levels of inflammatory markers, reduced concentration of adiponectin (a anti-inflammatory substance), and increased plasma cortisol concentration were also found among DM subjects. As the studies were limited by sample size, only a few risk factors were found significantly related to the carotid IMT. Age was the only common risk factor which was found to be correlated to the IMT of both the normoglycaemic and the DM/IGT subjects. (Abstract shortened by UMI.) / Fok Siu Pong. / "June 2005." / Adviser: Lester A. H. Critchley. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0173. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 200-228). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.