Chronic patellar tendinopathy is a degenerative tendon disorder characterized by chronic activity-related, anterior knee pain associated with localized tenderness, swelling and impaired performance, which is a common clinical problem in athletes. The pathogenesis of patellar tendinopathy is still largely unknown, although tendon overuse is the most commonly suggested etiological factor, and treatment is usually symptomatic. / Histopathologically, the predominant feature of patellar tendinopathy is tendinosis, which is characterized by progressive tissue degeneration with a failed healing response and the absence of inflammatory cells. Hypercellularity with non-tenocyte phenotype cells and tissue metaplasia, including hyaline metaplasia, fibrocartilaginous metaplasia and bony metaplasia were observed in clinical patellar tendinopathy samples. The degeneration of patellar tendon in patellar tendinopathy is an active cell-mediated process rather than a passive degenerative process. Using a patellar tendinopathy animal model, we observed the presence of chondrocytic and osteoblastic phenotype / markers in patellar tendinopathy samples with or without ossification, which was consistent with the findings in clinical samples. Interestingly, chondrocyte makers were expressed by healing tendon cells at week 2 which became round prior to their expression in the chondrocyte-like cells at week 4. This leads us to speculate that erroneous differentiation of tendon-derived stem cells (TDSCs) identified recently in tendon tissues by our group, to chondrocyte / osteoblasts, due to alteration of mechanical and biological microenvironment during overuse, may lead to the ectopic chondro-ossification and failed healing in patellar tendinopathy. Osteo-chondrogenic BMPs, such as BMP-2, BMP-4 and BMP-7 might be possible factors regulating the osteo-chondrogenic differentiation of TDSCs in the pathogenesis of patellar tendinopathy. / In conclusion, our results have provided new insights about the pathological mechanisms of patellar tendinopathy involving the resident stem cells, osteo-chondrogenic BMPs and mechanical overloading. Erroneous differentiation of TDSCs to chondrocytes / osteoblasts due to ectopic osteo-chondrogenic BMP-2 expression, which were induced by repetitive tensile loading stimulation, might account for the chondro-ossification and failed healing in patellar tendinopathy. Re-directing of stem cells for tenogenic differentiation by blocking the ectopic expression of osteo-chondrogenic BMPs may help to promote tendon healing in patellar tendinoapthy. / In this study, we hypothesized that (1) TDSCs isolated from pathological patellar tendon of the CI model will exhibit higher osteogenic and chondrogenic differentiation potential but lower proliferative capacity compared to TDSCs isolated from healthy patellar tendon. Rat pathological tendon in our collagenase-induced failed healing animal model will harbor more TDSCs compared to healthy patellar tendon. (2) Osteo-chondrogenic BMPs, such as BMP-2, BMP-4, and BMP-7, will be expressed ectopically in both preclinical and clinical samples of patellar tendinopathy. (3) BMP-2 will promote osteo-chondrogenic differentiation and inhibit tenogenic differentiation of TDSCs in vitro. (4) Repetitive tensile loading will increase the expression of BMP-2 in TDSCs in vitro. / Our results showed that TDSCs isolated from the collagenase-induced tendinopathic patellar tendon of the animal model exhibited higher osteogenic/chondrogenic differentiation potential as well as lower proliferative capacity, supporting that there might be some defects in the TDSCs from the animal model, which might undergo osteo-chondrogenic differentiation and hence reduced the pool of TDSCs for tendon repair in the development of patellar tendinopathy. The higher clonogenicity and increased yield of TDSCs in tendinopathic patellar tendon might be caused by a compensation for the impaired differentiation potential and proliferative capacity of TDSCs. The histopathological features of our clinical patellar tendinopathy were characterized by tissue degeneration. Non-tenocyte phenotype cells and tissue metaplasia, such as chondrocyte-like cells and endochondral ossification were also observed. We observed the ectopic expression of osteo-chondrogenic BMP-2, BMP-4 and BMP-7 in both our animal model and clinical samples of patellar tendinopathy, which might trigger the erroneous differentiation of TDSCs to non-tenocytes. Indeed, we further showed that BMP-2 could promote the osteo-chondrogenic and inhibit tenogenic differentiation of TDSCs in vitro, which might provide a possible explanation for ectopic chondro-ossification and failed healing in patellar tendinopathy. In addition, our results also showed that in vitro repetitive cyclic tensile loading could increase the expression of BMP-2 in TDSCs, which might provide a possible explanation for the ectopic expression of BMP-2 in patellar tendinopathy. / This study aimed to compare the osteogenic / chondrogenic differentiation potential, proliferative capacity and yield of TDSCs isolated from rat healthy patellar tendon and pathological tendon in our collagenase-induced failed tendon healing animal model of patellar tendinopathy in vitro. The histopathological characteristics of our clinical patellar tendinopathy with or without ossification were examined. The ectopic expression of BMP-2, BMP-4, and BMP-7 in both human and rat samples of patellar tendinopathy was also examined. The effects of BMP-2 on the osteogenic, chondrogenic and tenogenic differentiation of TDSCs was further investigated in vitro. The effect of repetitive tensile loading on the expression of BMP-2 in TDSCs was studied in vitro. / Rui, Yunfeng. / Advisers: Kai Ming Chan; Po Yee Lui. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 172-193). / 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, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Hepcidin is a well-known iron-regulatory hormone that plays a key role in maintaining peripheral iron homeostasis. The presence and wide-spread distribution of hepcidin in the brain suggests that this peptide may also be an important player in brain iron homeostasis. In this study, we tested the hypothesis that hepcidin exerts an important role in the regulation of brain iron content, which might benefit iron-associated NDs such as PD. We also examined the hypothesis that hepcidin could control iron transport processes via regulating iron transport proteins in the brain cells, thus maintaining brain iron homeostasis. / In conclusion, the results of the present study implied that hepcidin plays an important role in maintaining brain iron homeostasis. Hepcidin is beneficial for PD and this effect is related to its iron-regulatory effect via inhibiting iron accumulation in the substantia nigra. Hepcidin effectively controls iron uptake and release through regulating iron transport proteins expressions in the brain, which would contribute to brain iron homeostasis. Therefore, manipulation of hepcidin level in the brain has a potential to be developed into a novel preventive approach for the iron-associated NDs such as PD. / In the second part, we investigated the effect of hepcidin on the processes of iron uptake and release in the cultured brain cells including neurons, astrocytes and brain vascular endothelial cells (BVECs). The expressions of iron uptake proteins such as transferrin receptor 1 (TfR1) and divalent metal transporter 1 (DMT1) as well as the iron exporter ferroportin 1 (Fpn1) were also observed. We found that hepcidin reduced both iron uptake and release via decreasing iron transport proteins expressions in these brain cells, which would contribute to its iron regulatory effect. Finally, we further explored the mechanisms underlying the regulatory effect of hepcidin on the iron transporters in the last part, and found that the action of hepcidin in reducing TfR1 expression is a direct and cAMP-PKA (Cyclic Adenosine 3', 5'-monophosphate/ Protein Kinase-A) pathway-dependent event. / Iron is a transition trace metal essential for mammalian cellular and tissue viability. It also plays important roles in the central nervous system (CNS), including embryonic brain development, myelination, and neurotransmitters synthesis. However, abnormal iron accumulation has been demonstrated in a number of neurodegenerative diseases (NDs) such as Parkinson's (PD), Alzheimer's (AD) and Huntington's diseases (HD). Currently very little is known about the mechanisms involved in brain iron homeostasis and therefore it is not known why and how iron is abnormally increased in the brain. However, given the essential role that excess iron plays in the pathological processes in the NDs, to suppress the accumulated iron is expected to be an effective strategy to prevent and treat these NDs. / To investigate whether hepcidin could benefit iron-associated NDs including PD and whether this beneficial role is related to its iron-regulatory function in the brain, in the first part of study, we investigated the effects of hepcidin on the 6-hydroxydopamine (6-OHDA) in vitro and in vivo PD models. We found that in primary cultured mesencephalic (MES) neurons, hepcidin overexpression via adenovirus-hepcidin (Ad-hepcidin) infection prevented 6-OHDA-induced increase in cellular iron content and protected the MES neurons. In the 6-OHDA model of PD in vivo, overexpression of hepcidin in the substantia nigra via Ad-hepcidin intranigral injection significantly prevented iron accumulation and dopaminergic neurons loss in the pars compacta of substantia nigra (SNc). These effects were accompanied by a marked improvement in motor performance of the PD animals. These findings indicate that hepcidin could benefit iron-associated NDs such as PD and via its iron-regulatory role in the brain. / Du, Fang. / Adviser: Ya Ke. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 152-173). / 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, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

上皮間充質轉化（EMT），作為重要的生理和病理事件，廣泛的參與胚胎發育、組織纖維化病變及腫瘤轉移的過程。這一顯著的細胞表型變化包括上皮細胞失去緊密連接和極性，上皮細胞呈現纖維細胞形態以及增強的細胞移動性。囊性纖維變性跨膜電導調節器（CFTR）是一種廣泛表達於上皮細胞的氯離子和碳酸根離子通道。研究證實，CFTR 的蛋白轉運與上皮連接的形成和功能有關，同時 CFTR 的表達受到 EMT 誘導因子 HIF-1 和 TGF-β 的反向調節。另外，CFTR 的表達和功能被證實參與 EMT 相關信號分子 Wnt 和 NF-κB活性的調節。基於上述發現，本研究旨在闡述 CFTR 與 EMT 的相關性。 / CFTR 參與的腎上皮 EMT 以及後續的腎纖維化首先被關注。實驗表明，在腎上皮細胞（MDCK）中，小 RNA 介導的 CFTR 基因敲降或抑製劑引起的CFTR 通道功能缺陷均引起間充質細胞特徵的出現，包括纖維狀細胞形態、細胞連接分子 E-cadherin, ZO-1 和 Occludin 表達下調和間充質細胞標誌分子 Vimentin 和 N-cadherin 上調、上皮細胞跨膜電阻減低以及細胞遷徙能力的增強。有趣的是，在單側尿道結紮的腎纖維化模型中，CFTR 表達被顯著下調。同時，動物實驗證實一個最常見的 CFTR 分子突變（deltaF508 -/-）增加了單側尿道結紮導致的腎纖維化的程度。另外，在缺氧引起的 EMT 過程中CFTR 的表達顯著下調；同時，腎纖維化模型中，HIF-1 和 CFTR 的表達呈現負相關。結果提示，生理及病理的條件下，氧氣的調節可能作為 CFTR 下調及其後續事件的誘因。進一步實驗發現，CFTR 功能抑製或基因突變可以引起Wnt 的富集和 β-catenin 的細胞核轉移。基於以上的實驗結果，在腎纖維化的過程中，CFTR 參與了缺氧引起的 EMT 過程，並通過激活 Wnt/β-catenin 信號調節相關的下游因子。 / 第二部分集中探究了 CFTR 在癌細胞EMT 及腫瘤轉移中的作用及機制。實驗證實，在 TGF-β 誘導的腫瘤細胞 EMT 過程中，CFTR 表達被抑制。TGF-β 可能作為病理狀態下的調節因子，引起腫瘤細胞中 CFTR 表達下調及EMT。抑制 CFTR 通道功能或敲降其蛋白表達導致明顯的間充質細胞特徵，這一變化在不同來源的腫瘤細胞系中呈均一性。相對地，過表達 CFTR 引起細胞遷移和侵潤能力地顯著下降。在體實驗顯示，CFTR 表達與腫瘤的轉移能力呈現負相關。進一步機制研究證明，CFTR 通過調節多重的通路參與 EMT的過程。首先，uPA 的表達和活性受到 CFTR 的反向調節，並且這一調節作用是由激活的 NF-κB 介導的。其次，抑制 CFTR 通道功能引起 β-catenin 的細胞核轉移。 / 綜上所述，研究發現 CFTR 通過調節多重信號參與腎上皮及腫瘤細胞的 EMT。同時，研究顯示 CFTR 的表達和功能與腎纖維化及腫瘤轉移有關。此研究對相關疾病的診斷和預後具有潛在的提示作用。 / Epithelial-Mesenchymal Transition (EMT) is an intricate process by which epithelial cells lose their epithelial characteristics and acquire a mesenchymal-like phenotype. It is essential for numerous physiological and pathological processes, such as embryonic development, tissue fibrosis and cancer metastasis. The dramatic phenotype changes of EMT include loss of tight junctions and polarity, acquisition of a fibroblastic morphology and increased motility. The cystic fibrosis transmembrane regulator (CFTR) is known as an anion channel and extensively expressed in a variety of epithelial cells. Interestingly, the apical membrane expression of CFTR is reported to be required for the normal organization and function of epithelial junctions. Moreover, EMT inducers, such as HIF-1 and TGF-β, are known to suppress the expression of CFTR in epithelial cells. In addition, CFTR has been reported to be associated with expression and/or activity of Wnt and NF- κB, key factors known to be involved in EMT. Thus, we hypothesized that CFTR might play an important role in EMT. / In the first part of the study, the involvement of CFTR in EMT of kidney epithelial cells and renal fibrosis was investigated. Our experiments revealed that suppression of CFTR by either inhibitor or knockdown induced EMT in Madin- Darby canine kidney epithelial cells (MDCK). This was accompanied by the appearance of fibroblastic morphology, with reduced expression of epithelial junction proteins E-cadherin, ZO-1 and occludin and accumulated expression of the mensenchymal markers vimentin and N-cadherin, as well as reduced transepithelial resistance (TER) and enhanced migratory ability. Interestingly, the expression of CFTR was found significantly down-regulated in unilateral urethral obstruction (UUO) kidney. In addition, CFTR mutant (deltaF508 -/-), the most common mutation found in CF patients, increased the risk of renal fibrosis in UUO model. Our results showed that the expression of CFTR down-regulated in hypoxia induced-EMT in MDCK, and the expression of hypoxia-sensitive transcription factor, HIF-1, is inversely correlated with CFTR in UUO kidney. Accumulation of Wnt and translocation of β-catenin were also observed in CFTR inhibitors-treated MDCK and deltaF508 -/- UUO mice. Taken together, these findings suggest that CFTR may be involved in mediating hypoxia-induced EMT by influencing the Wnt/β-catenin signaling contributing to renal fibrosis. / In the second part of the study, the role of CFTR in EMT during cancer metastasis and the underlying mechanisms were investigated. Recent studies have demonstrated that cancer cells may reinstitute properties of developmental EMT including enhanced migration and invasion. On the other hand, the reverse process, known as mesenchymal-to-epithelial transition (MET), has been implicated in forming a secondary metastatic tumor. Using various tissue-derived cancer cell lines including human colorectal cancer cell line LIM1863, human lung carcinoma cell line A549, and human breast cancer cell lines MCF7 and MDA-MB-231, we report that induction of EMT by TGF-β sharply reduces CFTR expression in various tissue derived cancer cell lines, while overexpression of CFTR can reverse the TGF-β- induced EMT phenyotype. Interfering with CFTR function either by its specific inhibitor or lentiviral miRNA-mediated knockdown mimicks TGF-β-induced EMT and enhances cell migration and invasion. Ectopic overexpression of CFTR in a highly metastatic cancer cell lines downregulates EMT markers and suppresses cell invasion and migration in vitro, as well as the ability of the cells to metastasize to the lung in vivo. The EMT-suppressing effect of CFTR is found to be associated with its ability to alter NF-κB targeting urokinase-type plasminogen activator (uPA) and the nuclear translocation of β-catenin. Taken together, the present study has demonstrated a previously undefined role of CFTR as an EMT suppressor in cancer. / In summary, our findings have demonstrated a regulatory role of CFTR in EMT in both normal kidney epithelial cell line and various cancer cell lines. We conclude that CFTR plays important roles in renal fibrosis and cancer progression/metastasis by modulating EMT process through multiple pathways. The insights afforded by these studies will provide critical new information about the function of CFTR as a suppressor of EMT, which may have potential application in diagnosis and prognosis of fibrosis and cancer. / 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, Jieting. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 136-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Epithelial-Mesenchymal Transition --- p.1 / Chapter 1.1.1 --- Concept and features of EMT --- p.2 / Chapter 1.1.2 --- Roles of EMT in development and diseases --- p.10 / Chapter 1.1.3 --- The Regulators of EMT --- p.13 / Chapter 1.2 --- Structure and function of CFTR --- p.18 / Chapter 1.2.1 --- General structure and channel functions of CFTR --- p.18 / Chapter 1.2.2 --- Gene mutations and CF --- p.18 / Chapter 1.3 --- Potential role of CFTR in EMT --- p.20 / Chapter 1.3.1 --- CFTR in formation of cell-cell junction and membrane polarity --- p.20 / Chapter 1.3.2 --- CFTR and EMT inducers --- p.21 / Chapter 1.3.3 --- CFTR and EMT related pathways and factors --- p.22 / Chapter 1.4 --- Hypothesis and aim of the study --- p.22 / Chapter Chapter 2 --- CFTR involves in hypoxia induced EMT in renal fibrosis --- p.24 / Chapter 2.1 --- Abstract --- p.24 / Chapter 2.2 --- Introduction --- p.25 / Chapter 2.3 --- Results --- p.30 / Chapter 2.3.1 --- Knockdown of CFTR induces EMT in MDCK --- p.30 / Chapter 2.3.2 --- Inhibition of CFTR channel function induces EMT in MDCK --- p.30 / Chapter 2.3.3 --- CFTR is downregulated during the process of renal fibrosis --- p.36 / Chapter 2.3.4 --- CFTR defect increases the risk of renal fibrosis --- p.39 / Chapter 2.3.5 --- Hypoxia/HIF-1α rather than TGF-β as the inducer of CFTR repression during EMT and renal fibrosis --- p.44 / Chapter 2.3.6 --- CFTR as a negative regulator of Wnt/β-catenin signaling in renal epithelium --- p.51 / Chapter 2.4 --- Discussion --- p.57 / Chapter 2.5 --- Conclusion --- p.61 / Chapter 2.6 --- Materials and Methods --- p.61 / Chapter 2.6.1 --- Cell culture and treatments --- p.61 / Chapter 2.6.2 --- Plasmids and transient transfection --- p.62 / Chapter 2.6.3 --- Western blot analysis --- p.62 / Chapter 2.6.4 --- Measurement of trans epithelial electric resistance --- p.64 / Chapter 2.6.5 --- Wound-healing migration assay --- p.64 / Chapter 2.6.6 --- Animals and Obstructive model --- p.64 / Chapter 2.6.7 --- HE and Masson's trichrome stain --- p.65 / Chapter 2.6.8 --- Immunofluorescent and immunohistochemistry staining --- p.65 / Chapter 2.6.9 --- Statistical analysis --- p.66 / Chapter Chapter 3 --- CFTR down-regulation mediates EMT during cancer metastasis --- p.67 / Chapter 3.1 --- Abstract --- p.67 / Chapter 3.2 --- Introduction --- p.67 / Chapter 3.3 --- Results --- p.73 / Chapter 3.3.1 --- Repression of CFTR during TGF-β induced EMT in cancer cells --- p.73 / Chapter 3.3.2 --- Hypoxia does not have significant effect on CFTR expression --- p.78 / Chapter 3.3.3 --- Repression of CFTR channel function induces EMT in cancer cells --- p.81 / Chapter 3.3.4 --- Knockdown/overexpression of CFTR induces/inhibits EMT and malignant phenotypes --- p.84 / Chapter 3.3.5 --- CFTR inhibits lung metastasis in vivo --- p.94 / Chapter 3.3.6 --- Anti-metastatic effect of CFTR involves NF-κB targeting uPA --- p.104 / Chapter 3.3.7 --- Correlation between CFTR and β-catenin --- p.112 / Chapter 3.4 --- Discussion --- p.116 / Chapter 3.5 --- Conclusion --- p.122 / Chapter 3.6 --- Materials and methods --- p.122 / Chapter 3.6.1 --- Cell culture and treatments --- p.122 / Chapter 3.6.2 --- Lentiviral production and transduction --- p.123 / Chapter 3.6.3 --- Plasmids and stable transfection --- p.124 / Chapter 3.6.4 --- RT-PCR analysis --- p.124 / Chapter 3.6.5 --- Western blot analysis --- p.126 / Chapter 3.6.6 --- Immunofluorescence staining --- p.126 / Chapter 3.6.7 --- Cell growth assay --- p.127 / Chapter 3.6.8 --- Migration assay --- p.127 / Chapter 3.6.9 --- Invasion assay --- p.128 / Chapter 3.6.10 --- In vivo tumor growth assay --- p.128 / Chapter 3.6.11 --- In vivo metastasis assay --- p.128 / Chapter 3.6.12 --- Human EMT PCR array --- p.129 / Chapter 3.6.13 --- uPA activity assay --- p.129 / Chapter 3.6.14 --- Statistical analysis --- p.129 / Chapter Chapter 4 --- General discussion --- p.130 / Chapter 4.1 --- Normal function of CFTR in epithelial polarity and barrier function --- p.130 / Chapter 4.2 --- Down-regulation of CFTR is associated with EMT-related diseases --- p.131 / Chapter 4.3 --- CFTR functions as a central mediator of different EMT signals --- p.132 / Chapter 4.4 --- Future directions --- p.134 / Chapter 4.5 --- Conclusion --- p.135 / References --- p.136 / Declaration --- p.151

Hyperuricemia is the hallmark of gout. Pathogenic mechanisms of hyperuricemia include uric acid overproduction in the liver or underexcretion in the kidney. Current antihyperuricemic agents include xanthine oxidase inhibitors in which allopurinol is the most often prescribed. Inhibitors of renal urate reabsorption such as probenecid and benzbromarone are also employed. However, these existing antihyperuricemic agents possess some undesirable effects such as hypersensitivity towards allopurinol and hepatotoxicity associated with benzbromarone. Therefore, search for alternative antihyperuricemic agents with a more favorable toxicological profile or via mechanisms other than the above two mentioned is highly warranted. / The present project represents such an effort. Four in vitro experimental models were developed for the screening of new antihyperuricemic agents. The effects of the potential compounds from natural sources on the activities of phosphoribosyl pyrophosphate synthetase, hypoxanthine-guanine phosphoribosyl transferase and xanthine oxidase, as well as the uptake of urate through rat renal brush border membrane vesicles were investigated. Several compounds emerged with strong urate uptake inhibitory activities in which morin (3, 5, 7, 2', 4'-pentahydroxyflavone) was the most potent. Interestingly some of these compounds including morin were also demonstrated to be xanthine oxidase inhibitors. The subsequent in vivo experiment showed that morin indeed exhibited hypouricemic and uricosuric actions in an acute oxonate-induced hyperuricemic rat model. The uricosuric action of morin was hirther studied in transfected HEK293 cells expressing the human urate anion transporter 1 (hURATI) which is believed to regulate blood urate level by mediating urate reabsorption. In hURAT1-expressing HEK293 cells, urate uptake was significantly increased as compared to the non-transfected parental cells. Incorporation of morin into the uptake buffer could dose-dependently inhibit urate uptake in the transfected cells. Taken together our data indicated that morin is a potentially useful antihyperuricemic agent which acts by inhibiting xanthine oxidase and inhibiting urate reabsorption. In addition, the favorable safety profile of this natural compound makes it a potential candidate worthy of further investigations. / Yu Zhifeng. / "June 2006." / Advisers: Christopher H. K. Cheng; Wing Ping Fong. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1584. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 155-169). / 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.

First study determined the effects of genetic deletion of nNOS on the levels of spontaneous apoptosis in brain of young-adult (2-3 months) and aged (12-18 months) mice, using nNOS-knockout mice with age-matched B6129SF2/J mice as wild-type control. The results indicate that aging resulted in 11-fold increase in levels of apoptotic-DNA-fragmentation in B6129SF2/J mouse brain. nNOS-knockout mice demonstrated dramatic (72-fold) increases in levels of apoptotic-DNA-fragmentation in young-adult, but not aged, brains. Aging resulted in decreased number of nNOS-positive cells, increased number of iNOS-positive cells and no change of eNOS-positive cells in control mice. The data suggest that nNOS may serve an anti-apoptotic/neuroprotective role in young-adult mouse brain. However, because of diminished nNOS and increased iNOS with aging, this neuroprotective effect may become less effective in aged mice. / Fourth study showed that new microchip-electrophoresis-technology can be successfully used to identify and quantify levels of apoptosic-DNA-fragments in brain slice cultures, similar to our previous studies with CE-LIF. Because of the much greater throughput of microchip-electrophoresis-system, compared to CE-LIF, this new technology should help accelerate the progress of apoptosis research. / In second study, apoptotic effects of genetic deletion of either eNOS or iNOS were studied using young-adult (1-4 months) and aged (12-24 months) eNOS- or iNOS-knockout mice with age-matched C57BL/6J wild-type control mice. The data show that both young-adult and aged iNOS-knockout mice had dramatically (8- to 36-fold) higher levels of apoptotic-DNA-fragmentation compared to control, especially noticeable in hippocampus and medulla oblongata. Both young-adult and aged eNOS-knockout mice also had dramatically (18- to 35-fold) higher levels of apoptotic-DNA-fragmentation compared to control, especially in cerebral cortex, hippocampus and medulla oblongata. The data suggest that both iNOS and eNOS provide neuroprotective effects, helping to limit the extent of spontaneous apoptosis in brain of young-adult and aged mice. / Nitric oxide (NO) has either pro-apoptotic or anti-apoptotic effects on neuronal cells, depending on concentration of NO produced by different source of NO synthases (NOSs) including neuronal-NO-synthase (nNOS/NOS-1), inducible-NO-synthase (iNOS/NOS-2) or endothelial-NO-synthase (eNOS/NOS-3) and possibly age of the individual. The present study determines if genetic deletion of nNOS, iNOS or eNOS alters levels of aging-induced apoptosis in vivo and hydrogen peroxide (H2O2)-induced-apoptosis in organotypic brain slice cultures using NOS-knockout mice. The quantitative ultrasensitive techniques using capillary-electrophoresis with laser-induced-fluorescent detector (CE-LIF) and Cell-Death---Detection-ELISA were used as novel ways to accurately measure the levels of apoptotic-DNA-fragmentation. Expressions of different forms of NOSs were determined by immunohistochemical-staining. / Third study determined H2O2-induced apoptosis in hippocampal and cerebellar slices from young-adult (8-10 weeks) and aged (12-24 months) C57BL/6J control mice, as well as iNOS- and eNOS-knockout mice (determined by Cell-Death-Detection-ELISA measuring levels of apoptotic-DNA-fragmentation). The data show spontaneous onset of apoptosis occurred in both hippocampal and cerebellar slices during culturing, beginning at 24 hours and progressively increasing for 48--72 hours. Staurosporine (positive-control) and H2 O2 both caused time-dependent increases in apoptosis in both hippocampal and cerebellar slices, compared to time-matched controls. Lastly, genetic deletion of iNOS greatly reduced levels of spontaneous apoptosis in young hippocampus and aged cerebellum, suggesting iNOS had contributed to induction of spontaneous apoptosis. / Chow Wing Han Vivian. / "Dec 2005." / Advisers: Siew Boon Chew Cheng; Ray Ronald Fiscus. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6218. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 144-153). / 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.

Introdução: Os mecanismos fisiopatológicos da asma grave resistente ao tratamento (STRA) em crianças não está totalmente elucidado e parece diferir do observado em adultos, justificando investigações específicas neste grupo de pacientes. O escarro induzido é método útil para identificar fenótipos e endotipos de asma grave através de marcadores inflamatórios. O objetivo deste estudo foi investigar os padrões inflamatórios de crianças com STRA através escarro induzido e comparar com um grupo de crianças com asma grave que atingiram o controle. Métodos: Crianças (6-18 anos) com diagnóstico de asma grave (critério GINA) em tratamento a pelo menos 6 meses em um centro de referência foram avaliadas em um coorte prospectivo por 3 meses (3 visitas consecutivas). Foi averiguada técnica inalatória, adesão ao tratamento e investigado as principais comorbidades. Realizado coleta de escarro induzido para análise citológica e avaliação quantitativa de citocinas do sobrenadante, espirometria, pletismografia e medidas da FeNO. Após período de seguimento, os pacientes foram classificados em dois grupos: asma grave controlada e asma grave resistente ao tratamento conforme critérios da ATS/ERS. Resultados: Foram incluídos 40 pacientes (idade média 12,8 anos; 62,5% sexo masculino), sendo 13 (32,5%) classificados como STRA após o período de seguimento. A mediana do número de exacerbações foi maior e do escore de ACT menor nos pacientes STRA e esta diferença foi significativa. Não foram encontradas diferenças significativas: nos dados demográficos, nos parâmetros funcionais espirométricos e de pletismografia (CVF, VEF1, VEF/CV, FEF 25-75%, LTC, RV, RV/LTC, resistência e condutância das vias aéreas) e nos valores de FeNO quando comparado o grupo de pacientes controlados com o de STRA. O padrão inflamatório eosinofílico foi predominante nos dois grupos de pacientes, entretanto, o grupo STRA apresentou porcentagem proporcionalmente maior de neutrófilos no escarro comparados com o grupo de asma grave controlada, na visita 3 e também na visita 1 quando analisados retrospectivamente (p < 0,05). As medianas nos níveis das citocinas IL10, GM-CSF, INFy e TNFalfa no escarro foram significativamente maiores no grupo STRA quando comparado ao grupo controlado (p < 0,05) e o GM-CSF e TNF-alfa apresentaram correlação inversa com escore de ACT. Conclusão: Nesta coorte prospectiva, os parâmetros funcionais e a FeNO não discriminaram crianças com STRA dos que atingiram o controle. A presença de neutrófilos no escarro e das citocinas IL10, INFy e, particularmente, GM-CSF e TNFalfa podem ter para um papel na resistência ao tratamento da asma grave em crianças e adolescentes. Antagonistas específicos dessas citocinas podem no futuro representar uma estratégia na terapêutica / Background: The pathophysiological mechanisms of severe therapyresistant asthma (STRA) in children are not fully elucidated and seem to differ from findings in adults, thus justifying specific research on children. Induced sputum is useful for detecting phenotypes and endotypes of severe asthma via inflammatory markers. The aim of the present study was to investigate the inflammatory patterns of children with STRA by the induced sputum method and to compare them with a group of children who achieved control of severe asthma. Methods: A prospective cohort of children (6-18 years old) diagnosed with severe asthma (Global Initiative for Asthma - GINA criteria) and in treatment for at least 6 months at a reference center was assessed for 3 months (3 consecutive visits). Inhalation technique, adherence to treatment and main comorbidities were assessed. Induced sputum samples were collected for cytology analysis and quantitative assessment of cytokines in the supernatant; the participants were also subjected to spirometry, plethysmography and fractional exhaled nitric oxide (FeNO) measurements. At the end of follow-up, the patients were classified into two groups: controlled severe asthma and STRA according to the European Respiratory Society and American Thoracic Society (ERS/ATS) criteria. Results: Forty patients were included (average age 12.8 years old; 62.5% male); 13 (32.5%) were classified as STRA at the end of follow up. The median number of exacerbations was higher and the Asthma Control Test (ACT) score was lower in the STRA group; these differences were significant. Significant differences were not found relative to demographic data, spirometry and plethysmography function parameters [forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), ratio of FEV1 to slow vital capacity (FEV1/SCV), forced expiratory flow at 25-75% of FVC (FEF 25-75%), total lung capacity (TLC), residual volume (RV), RV/TLC, airway resistance and conductance] and FeNO after comparison of the STRA and controlled asthma groups. The eosinophilic inflammatory pattern predominated in both groups; however, the STRA group showed a proportionally higher percentage of sputum neutrophils compared with the controlled asthma group at visit 3 and visit 1 upon retrospective analysis (p<0.05). The median sputum levels of the cytokines IL-10, GM-CSF, IFN-y and TNF-alpha were significantly higher in the STRA group compared with the controlled asthma group (p < 0.05); GM-CSF and TNF-? showed inverse correlations with ACT scores. Conclusion: In the analyzed prospective cohort, functional parameters and FeNO did not discriminate between children with STRA and children with controlled asthma. The presence of neutrophils and the cytokines IL-10, IFN-y and, more particularly, TNF-alpha and GM-CSF in the sputum might have a role in resistance to treatment for severe asthma among children and adolescents. Antagonists specific for these cytokines might represent a therapeutic strategy in the future

Ho, Tik Shun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 88-102). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.vii / Table of Contents --- p.viii / List of Table --- p.x / List of Figures --- p.xi / List of Abbreviations --- p.xiii / Chapter CHAPTER 1 --- General Introduction --- p.1 / Chapter 1.1 --- Fatty Acid Synthase (FAS) - 7-domain multifunctional enzyme --- p.1 / Chapter 1.1.1 --- Functions --- p.1 / Chapter 1.1.2 --- Structure --- p.2 / Chapter 1.2 --- Fatty Acid biosynthesis reactions --- p.4 / Chapter 1.3 --- Malonyl Coenzyme A - An important mediator in lipogenesis --- p.7 / Chapter 1.4 --- FAS expression in different histotypes --- p.8 / Chapter 1.4.1 --- FAS in normal cells --- p.8 / Chapter 1.4.2 --- FAS in pathological cells --- p.8 / Chapter 1.4.3 --- Tumor-associated FAS (Oncogenic antigen-519) in cancer cells --- p.9 / Chapter 1.5 --- FAS signaling models in breast and prostate cancers --- p.12 / Chapter 1.5.1 --- Association between FAS and PI3K／Akt pathway --- p.12 / Chapter 1.5.2 --- Hypothetical model of FAS hyperactivity in breast and prostate cancer cells --- p.13 / Chapter 1.6 --- FAS inhibition to tackle cancer cell growth --- p.15 / Chapter 1.6.1 --- FAS inhibitors --- p.15 / Chapter 1.6.1.1 --- Cerulenin --- p.16 / Chapter 1.6.1.2 --- C75 --- p.17 / Chapter 1.6.2 --- Small interfering RNA --- p.17 / Chapter 1.7 --- FAS inhibition to enhance chemoresistant cancer cells sensitivity to drugs --- p.19 / Chapter 1.8 --- Hypothesis --- p.20 / Chapter CHAPTER 2 --- Methods and Materials --- p.21 / Chapter 2.1 --- Chemicals and antibodies --- p.21 / Chapter 2.2 --- Cell cultures --- p.21 / Chapter 2.3 --- MTT assay --- p.22 / Chapter 2.4 --- 5-Bromo-2'-deoxyuridine (BrdU)-labeling cell proliferation assay --- p.22 / Chapter 2.5 --- Cytotoxicity detection assay of LDH release --- p.23 / Chapter 2.6 --- DNA flow cytometry --- p.23 / Chapter 2.7 --- Confocal micocropy --- p.24 / Chapter 2.8 --- Immunoblot analysis --- p.24 / Chapter 2.8.1 --- Preparation of protein lysates --- p.24 / Chapter 2.8.2 --- Immunoblotting --- p.25 / Chapter 2.9 --- Caspase inhibitor studies --- p.26 / Chapter 2.10 --- Analysis of mitochondrial membrane potential --- p.26 / Chapter 2.11 --- Determination of caspase activities --- p.27 / Chapter 2.12 --- siRNA transfection --- p.27 / Chapter 2.13 --- Statistical analysis --- p.28 / Chapter CHAPTER 3 --- Results --- p.29 / Chapter 3.1 --- Cytostatic & cytotoxic studies of FAS inhibitors on human cancer cells --- p.29 / Chapter 3.1.1 --- Cerulenin and C75 suppress cell growth of different cancer histotypes --- p.29 / Chapter 3.1.2 --- Cerulenin and C75 suppress cell growth of A-375 dose- and time-dependently --- p.32 / Chapter 3.1.3 --- Cerulenin and C75 exert cytotoxic effect on A-375 but not normal skin HS68 cells --- p.36 / Chapter 3.1.4 --- Cerulenin and C75 arrest cell cycle progression and induce apoptosis with DNA Fragmentation --- p.39 / Chapter 3.2 --- Mechanistic studies of FAS inhibitors in A-375 cells --- p.46 / Chapter 3.2.1 --- Cerulenin and C75 induce caspase-dependent apoptosis --- p.46 / Chapter 3.2.2 --- Cerulenin- and C75-induced apoptosis involve extrinsic death receptor pathway --- p.52 / Chapter 3.2.3 --- Cerulenin- and C75-induced apoptosis involve intrinsic mitochondrial pathway --- p.57 / Chapter 3.2.4 --- Extrinsic death receptor pathway serves as a pioneer and links with intrinsic mitochondrial pathway in cerulenin- and C75-induced apoptosis --- p.65 / Chapter 3.3 --- Small interfering RNA on Fatty Acid Synthase (FAS siRNA) --- p.68 / Chapter 3.3.1 --- FAS siRNA induces PARP cleavage --- p.68 / Chapter 3.3.2 --- FAS siRNA triggers caspase-dependent apoptosis as FAS inhibitors --- p.70 / Chapter CHAPTER 4 --- Discussion --- p.72 / Chapter CHAPTER 5 --- Future Prospect --- p.85 / Chapter CHAPTER 6 --- References --- p.88

Le paludisme est une maladie tropicale causée par un parasite du genre Plasmodium. Chez l’Homme, un niveau élevé de phospholipase A2 sécrétée de groupe IIA humaine (hGIIA) est mesuré dans le plasma des patients impaludés. Cette enzyme est connue pour son rôle antibactérien et pro-inflammatoire. Cependant, son rôle dans le paludisme n’a jamais été exploré. Pour comprendre le rôle in vivo de la hGIIA dans cette pathologie, nous avons entrepris la caractérisation hématologique, histopathologique et immunohistochimique de l’infection de souris C57BL/6, transgéniques (Tg+) pour l’enzyme humaine, par l’espèce murine Plasmodium chabaudi chabaudi 864VD. Ce modèle reproduit un paludisme non létal. Nos résultats ont permis d’établir que les souris Tg+ ont un meilleur contrôle de l’infection au moment du pic de crise parasitaire (J14 post-inoculation), avec une diminution de 27% de la parasitémie, comparé aux souris « littermates » non transgéniques (Tg-). L’injection de hGIIA recombinante aux jours 12, 13 et 14 p.i. (0,125 mg/kg deux fois par jour) à des souris C57BL/6 wild-type (WT) infectées par P. c. chabaudi 864VD provoque une diminution d’environ 19% de la parasitémie à J14 p.i., démontrant un rôle direct de la hGIIA dans la diminution de la population parasitaire. Les données hématologiques montrent que l’infection chez la souris Tg+ provoque une anémie plus durable que chez la souris Tg- et une élévation nettement plus importante du nombre de leucocytes, en particulier des polynucléaires neutrophiles. Chez la souris Tg+ parasitée, on observe aussi l’activation d’un nombre important de lymphocytes et une activation spécifique des monocytes avant le pic de crise. Chez la souris Tg- infectée, les données histologiques mettent en avant une meilleure récupération des lésions histopathologiques du foie et une hyperplasie des lymphocytes B dans la rate, tandis que les souris Tg+ infectées présentent des lésions hépatiques tardives et une hématopoïèse extramédullaire splénique. Les résultats des analyses par RT-qPCR suggèrent que l’ARNm de la hGIIA augmente au pic parasitaire dans le foie des souris Tg+ infectées, mais diminue dans la rate et les cellules sanguines. L’injection de hGIIA recombinante au début de la phase patente est sans effet sur la parasitémie, ce qui laisse supposer que des événements plus tardifs dans l’infection sont nécessaires à l’activité antiparasitaire de l’enzyme. L’étude du rôle des lipoprotéines oxydées comme substrat potentiel de l’activité antiparasitaire de l’enzyme, basée sur des résultats in vitro, est abordée. En conclusion, nos études ont permis de dresser un tableau large de l’infection à Plasmodium chez la souris exprimant la hGIIA, et ouvrent de nouvelles perspectives dans l’analyse du rôle de l’enzyme dans la physiopathologie du paludisme. / Malaria is a tropical disease caused by a parasite of the Plasmodium genus. High levels of circulating human group IIA secreted phospholipase A2 (hGIIA) have been reported in malaria patients. The enzyme is well known for its bactericidal and pro-inflammatory actions. However, so far its role in malaria is unknown. In order to address the in vivo role of hGIIA in malaria, we performed a hematological, histopathological and immunohistochemical characterization of C57BL/6 hGIIA transgenic mice (Tg+ mice) infected with P. chabaudi chabaudi (864VD strain), a murine Plasmodium species and strain which causes non-lethal chronic malaria. Infected Tg+ mice present a 27% reduction of parasitaemia at the peak of infection (D14 post-inoculation, p.i.) compared to infected non-transgenic littermates (Tg- mice). Intraperitoneal injection of recombinant hGIIA at D12, D13 and D14 p.i. (0.125 mg/kg twice a day) into P. chabaudi 864VD-infected WT C57BL/6 mice leads to a 19% reduction of the parasitaemia at D14 p.i., demonstrating the direct and acute role of hGIIA in lowering parasite population and presumably ruling out a potential effect linked to chronic overexpression of hGIIA in Tg+ mice. Hematological data show a durable anemia in Tg+ mice compared to Tg- mice during the infection and an important increase of leucocytes, especially of polynuclear neutrophils. The parasitized Tg+ mouse also presents a higher activation of lymphocytes and a specific activation of monocyte cells at the pic of crisis. In the infected Tg- mouse, histological data show a better histopathological recovery in the liver and B cells hyperplasia in the spleen, whereas the infected Tg+ mouse presents late hepatic injuries and splenic extra-medullar hematopoiesis. RT-qPCR analyses suggest that hGIIA mRNA increases at the pic of infection in the liver of infected Tg+ mice, but decreases in spleen and blood. Intraperitoneal injection of recombinant hGIIA at the patent phase is without effect on parasitaemia, which suggests that later infection events are needed for the enzyme antiparasitic activity. Involvement of oxidized-lipoproteins as potential hGIIA substrates, based on in vitro studies, is discussed. In conclusion, our studies allowed us to elaborate a larger picture of the infection of Plasmodium in the mice expressing hGIIA and open new perspectives in the analysis of the role of the enzyme in malaria pathophysiology.

Les récepteurs nucléaires aux œstrogènes, ERα66 et ERβ1, sont les principaux médiateurs des effets des œstrogènes. Ces hormones régulent le développement physiologique de la glande mammaire mais participent aussi à la progression du cancer sein. L’expression d’ERα66 est d’ailleurs utilisée dans la classification moléculaire des tumeurs mammaires afin d’orienter la stratégie thérapeutique. Depuis son clonage, le variant des récepteurs alpha aux œstrogènes, ERα36, a été principalement décrit dans la littérature pour son rôle dans la progression des tumeurs mammaires et dans l’acquisition de résistances aux anti-œstrogènes comme le Tamoxifène. Si une forte expression d’ERα36 dans les cellules cancéreuses mammaires apparaît nettement comme un facteur de mauvais pronostic, peu de données sont disponibles concernant son rôle dans le développement de la glande mammaire saine. C’est pourquoi le premier objectif de ce travail était de déterminer le rôle d’ERα36 dans le développement physiologique de cette glande. Grâce à une approche pluridisciplinaire, incluant des études in vivo sur un modèle de souris transgéniques MMTV-ERα36 et des études in vitro et in silico sur des cellules épithéliales mammaires immortalisées, nous avons montré que l’expression d’ERα36 perturbe le phénotype des cellules épithéliales mammaires et conduit à l’apparition d’altérations structurales des canaux mammaires à l’âge adulte. De plus, nous avons mis en évidence que les alkylphénols, qui sont des perturbateurs endocriniens œstrogèno-mimétiques, stimulent l’expression endogène de ce variant dans les cellules MCF-10A et augmentent leurs capacités migratoires sans pour autant amplifier les effets d’ERα36 sur l’histologie des canaux mammaires. En parallèle, afin de mieux comprendre l’implication d’ERα36 au moment de l’initiation et de la progression tumorale, nous avons étudié les modalités de régulation de l’expression de ce variant dans les cellules cancéreuses mammaires. Les résultats obtenus indiquent que l’expression d’ERα36 est positivement corrélée au statut de méthylation de sa région promotrice et que l’ARNm codant ce variant est la cible d’hsa-miR136-5p. Enfin, le dernier objectif de ce travail était de développer une approche visant à identifier in silico de nouveaux partenaires d’ERα36. L’ensemble de ce travail s’inscrit dans une démarche de raffinement de la classification moléculaire actuelle des tumeurs mammaires en y ajoutant une composante associée à l’expression d’ERα36. / The estrogen nuclear receptors, represented by the canonical forms ERα66 and ERβ1, are the main mediators of the estrogenic effects in mammals. These hormones, which regulate the physiological development of the mammary gland, participate in the initiation and progression of breast cancer. In fact, ERα66 expression is a key molecular classifier of breast tumors used in order to guide the therapeutic strategies toward hormonotherapy. However, in 30% of cases, therapeutic failures are observed, which highlights the importance of identifying new biomarkers. The estrogen receptor variant, ERα36, has been cloned in 2005 and mainly described in the literature to be involved in the progression of mammary tumors and in the acquired resistance to anti-estrogen drugs, such as Tamoxifen. Even if a high expression of ERα36 in breast cancer cells appears to be associated with a poor prognosis, few data are available concerning its role in the normal development of the mammary gland. Therefore, the aim of this work was to determine the role of ERα36 in the physiological development of the mammary gland. Thanks to a multidisciplinary approach, that combines in vivo studies on MMTV-ERα36 transgenic mice, and in vitro and in silico studies on immortalized normal epithelial mammary cells (MCF-10A), we showed that ERα36 expression is sufficient to disturb the mammary epithelial cells phenotype, leading to the emergence of structural alterations of mammary ducts at adulthood. Moreover, we showed that exposure to the estrogen mimicking compounds alkylphenols stimulates the endogenous expression of this variant in MCF-10A cells, and increases their migratory ability. Then, in order to get a better understanding of ERα36 contribution to tumor initiation and/or progression, we studied classical and epigenetic regulation of this variant expression in breast cancer cells. Our results show that ERα36 expression is positively correlated with the methylation status of its promoter region, and that the ERα36 mRNA is the target of the microRNA, has-miR-136-5p. Finally, the last aim of this work was to develop a bioinformatic approach in order to study the ERα36 partners. To summarize, all of this work falls within a need of the current breast tumor molecular classification refinement by adding a component related with ERα36 expression.

published_or_final_version / Anaesthesiology / Doctoral / Doctor of Philosophy