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The focus of this research was to investigate the use of an immortalized bovine mammary epithelial cell line as a starting material for xenogeneic transplantation into the mammary glands of immunocompetent recipients. PSG-5 cells (a clonal derivative of the MAC-T cell line engineered to express ovine IGF-I ) were transplanted into the cleared mammary fat pads of recipient mice. Following transplantation, spheroidal cell structures were observed in the cleared mammary fat pads of immunocompetent control mice and in mice exposed to PSG-5 cells during fetal development. Spheroidal cell structures were not observed in glands that had not received cell transplants. The success of this xenogeneic transplantation prompted the development of a MAC-T cell clone expressing a bacterial β-galactosidase (βMAC-T's) for use as a histological marker protein. Studies were then performed to determine the most appropriate age and location for cell transplantation into ovine recipients. Between three and 12 weeks of age, parenchymal volume in the mammary glands collected from e\ves in this study (n=4/age group: 3,6,9, and 12 weeks) increased nearly lO-fold (3.8cm³ to 34.5cm³ ). Total gland volume increased approximately 5-fold (67.3cm³ to 316.2cm³ ). Based on these determinations of parenchymal and glandular volumes, we determined that transplantation should begin with lambs at about three weeks of age. This data provides a starting point to begin trials using βMAC-T cells, which have been engineered to express a histological marker protein, for transplantation into intact ovine and murine mammary glands. / Master of Science

Human airway epithelial cells (HAECs) play a pivotal role in creating a mechanical barrier to prevent environmental insults from entering deeper into the lung tissue and in facilitating host defence against pathogens and allergens by producing immune mediators and recruiting inflammatory cells. ABCF1, is a unique member of the ABC transporter family that it is highly expressed in the airway epithelium, however, its function in HAECs is currently not known.In this thesis, we explored the role of ABCF1 as a dsDNA viral sensor in HAECs. Our findings demonstrated that while ABCF1 is required for an immune response to a double-stranded DNA (dsDNA) viral mimic, VACV-70, our transcriptomic analysis suggested a role in pro-inflammatory responses downstream of toll-like receptors (TLR) 3 and 4 signalling pathways. We followed this outcome by investigating ABCF1 in mediating pro-inflammatory responses to TNF-α and Poly(I:C) through A20, NF-κB and IRF-3 regulated signalling pathways. Our study demonstrated that Poly(I:C) and TNF-α induced IL-8 are regulated by ABCF1 through pathways independent of NF-κB, and IRF-3 activation, although the exact mechanism remains unclear. The next approach was to run a hypothesis-free in silico investigation of the ABCF1 protein-protein interaction (PPI) network using publicly available databases and Gene Ontology (GO) term enrichment analysis. Following our in silico results of ABCF1 protein interactors, we validated a novel interaction of ABCF1 and SYK in human airway epithelial cells following Poly(I:C) stimulation. We have demonstrated that silencing ABCF1 under stimulation by VACV-70, TNF-α and Poly(I:C) in HAECs affects the induction of immune mediators, and a candidate protein interaction partner, SYK, is involved in immune signalling, however its exact mechanism is not defined. We propose that further insights into the functions of ABCF1 may aid in understanding how HAECs maintain mucosal immune homeostasis. / Thesis / Doctor of Philosophy (Medical Science) / The human lungs are exposed to over 10,000 litres of air each day from normal respiration, and it is the first point of contact between the outside environment and the internal anatomy. The cells on the surface of the air passages in the lungs are called human airway epithelial cells (HAECs), and they represent a critical defence against inhaled foreign objects that may include air pollution, allergens, bacteria, and viruses. HAECs have a group of proteins called ABC transporters, that are capable of different activities that are essential for maintaining normal lung health. One unique ABC transporter called ABCF1 was found to regulate defences against viral and bacterial infections in non-lung cells. It is unclear whether ABCF1 has the same function and protective capacity in HAECs. In this Ph.D. thesis, we investigated how ABCF1 functions in HAECs to detect and respond to respiratory infections. By understanding how ABCF1 is involved in protecting the lungs against these infections, novel treatments can be developed to minimize morbidity and mortality in both healthy and vulnerable individuals. In our studies, we evaluated the changes in the response of HAECs that had normal or absent levels of the ABCF1 gene under conditions that resemble an infection. We used computational tools to help us investigate the proteins that interact with ABCF1 and predict their potential function. Our studies have concluded that ABCF1 does have a protective capacity in HAECs, however, we have yet to elucidate how and what other proteins are involved to help it function.

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

Trichomonas vaginalis é o agente etiológico da doença sexualmente transmissível não viral mais comum no mundo, sendo registrados aproximadamente 276 milhões de novos casos de tricomonose a cada ano. O estabelecimento da infecção se deve principalmente à capacidade de adesão do parasito às células epiteliais vaginais, cervicais ou de próstata, seguida pela intensa reação inflamatória, resultado da infiltração de neutrófilos no sítio da infecção. Nucleotídeos e nucleosídeos, especialmente ATP e adenosina, são liberados para o espaço extracelular por células em situações de estresse ou injúria tecidual e desenvolvem seus efeitos sinalizadores através da ativação de purinoceptores. Ainda, as ectonucleotidases, NTPDase e ecto-5’-nucleotidase, são capazes de hidrolisar os nucleotídeos gerando adenosina e finalmente, a enzima adenosina deaminase (ADA) é responsável pela conversão de adenosina em inosina. A expressão gênica de cinco NTPDases putativas presentes no genoma de T. vaginalis foram investigadas, assim como o envolvimento da sinalização purinérgica na relação parasito-hospedeiro. Nossos resultados mostraram que diferentes isolados de T. vaginalis expressam os genes TvNTPDase1, 2, 3, 4 e 5, sendo observado o maior número de transcritos para TvNTPDase1, 2 e 4. A sequência preditiva de aminoácidos revelou a presença das cinco regiões conservadas da apirase, domínios transmembrana, sítios de fosforilação, peptídeos sinais e os prováveis sítios ativos da enzima. A análise filogenética demonstrou maior similaridade das TvNTPDases com as formas intracelulares da enzima, como as NTPDases 4 e 7 humanas e a de Saccharomyces cerevisiae. Além disso, a restrição de soro promoveu aumento significativo da atividade da NTPDase de T. vaginalis, no entanto sem corresponder com o aumento de expressão gênica de determinada(s) sequência(s). Quanto à participação da sinalização purinérgica na resposta inflamatória de células do hospedeiro frente ao parasito, foram utilizados como modelos celulares as células epiteliais vaginais (HMVII), cervicais (HeLa) e neutrófilos humanos. As linhagens HMVII e HeLa mostraram expressar todos os subtipos de receptores P1, P2X e P2Y e XI os diferentes isolados de T. vaginalis, que foram cocultivados com as células, mostraram hidrolisar eficientemente os nucleotídeos ATP, ADP e AMP. Ainda, o isolado clínico fresco TV-LACM6 foi o único a apresentar elevada citotoxicidade frente às células epiteliais vaginais e cervicais, no entanto não foi detectado aumento da liberação de ATP pelas células após o cocultivo, provavelmente devido à alta atividade da enzima NTPDase observada nesse isolado. Os trofozoítos de T. vaginalis não foram capazes de aumentar a produção de IL-8 e IL-6 pelas linhagens HMVII e HeLa, e apenas os isolados ATCC30236 e TV-LACM6 causaram aumento na secreção da citocina MIP-3α pelas células epiteliais cervicais. Finalmente, o nucleotídeo ATP e o nucleosídeo adenosina não modularam a produção dos mediadores inflamatórios investigados. Em relação aos neutrófilos, estes mostraram aumentar a produção de espécies reativas de oxigênio (ERO) e IL-8 após incubação com os trofozoítos de T. vaginalis. Os nucleotídeos e nucleosídeos da adenina e guanina não produziram efeito na produção de ERO e IL-8; no entanto, quando o nucleosídeo adenosina foi incubado junto com o inibidor da enzima ADA (EHNA) observou-se uma redução significativa da produção de ERO e IL-8 pelos neutrófilos, devido à inibição da ADA e consequentemente, ao aumento da concentração de adenosina disponível no meio extracelular. Os nossos resultados indicaram a ativação do receptor A1 dos neutrófilos nessa condição. O conjunto de dados aqui obtidos contribuiu para uma melhor caracterização da família de enzimas NTPDases de T. vaginalis assim como para um maior conhecimento acerca da influência da sinalização purinérgica na relação parasito-hospedeiro. / Trichomonas vaginalis is the agent of the most common non-viral sexually transmitted disease worldwide, causing 276.4 million new cases a year. The establishment of the infection is closely related to the parasite ability to adhere to vaginal, cervical and prostate epithelial cells, followed by an intense inflammatory response as result of neutrophil infiltration. Nucleotides and nucleosides, mainly ATP and adenosine, are released into the extracellular space by cells under stress or injury and they exert their signaling effects through activation of the purinoceptors. Moreover, the ectonucleotidases, NTPDase and ecto-5'-nucleotidase, are capable of hydrolyzing the nucleotides producing adenosine and finally, the adenosine deaminase (ADA) is responsible for the conversion of adenosine to inosine. We investigated the gene expression of five putative NTPDases found in T. vaginalis genome as well as the involvement of purinergic signaling on the host-parasite relationship. Our results showed that different T. vaginalis isolates are able to express TvNTPDase1, 2, 3, 4 and 5 and that TvNTPDase1, 2 and 4 are the most expressed genes. Predictive amino acid sequence revealed the presence of the five apyrase conserved regions, transmembrane domains, phosphorylation sites, signal peptides and the active sites. Phylogenetic analysis showed that TvNTPDases share more similarity with the intracellular enzymes, such as human NTPDase 4 and 7 and Saccharomyces cerevisiae NTPDase. In addition, the serum limitation caused a significant increase in NTPDase activity, but without association with the gene expression of a specific TvNTPDase sequence. Regarding the participation of purinergic signaling on the inflammatory responses against the parasite, the vaginal (HMVII) and cervical (HeLa) epithelial cells and the human neutrophils were used as cellular models. HMVII and HeLa cell lines showed to express all subtypes of P1, P2X and P2Y receptors and the different T. vaginalis isolates, which were co-cultured with the cells, showed to hydrolyze efficiently ATP, ADP and AMP. Furthermore, only the fresh clinical isolate, TV-LACM6, caused a profound cytotoxicity against the vaginal and cervical epithelial cells. Interestingly, it was not detected an increase in ATP release by the cells after cocultivation, probably due to the high NTPDase activity dislplayed by TV-LACM6 isolate. The T. vaginalis trophozoites were not able to increase the production of IL-8 and IL-6 by HMVII and HeLa cells and only ATCC30236 and TV-LACM6 isolates enhanced MIP-3α secretion by the cervical epithelial cells. Finally, neither ATP nor adenosine has modulated the production of the inflammatory mediators here investigated. Considering the neutrophils, T. vaginalis stimulated the production of reactive oxygen species (ROS) and IL-8 by these immune cells and both adenine as guanine nucleotides and nucleosides did not cause any effect on ROS and IL-8 levels. However, when adenosine was incubated with an ADA inhibitor (EHNA) we observed a significant reduction of ROS and IL-8 production by neutrophils, due to inhibition of ADA with a subsequent increase of adenosine concentration in the extracellular milieu. . Our results suggested the participation of A1 receptor in this condition. The data set obtained in this study contributed to the characterization of T. vaginalis NTPDases family as well as to a better understanding of the influence of purinergic signaling on host-parasite relationship.

Zhu Jinxia. / "July 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 142-170). / 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.

Fung, Chun Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 121-135). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgement --- p.ii / Abbreviations --- p.iii / Abstract in English --- p.v / Abstract in Chinese --- p.vii / Table of Contents --- p.ix / List of Figures --- p.xii / Chapter Chapter 1 - --- Introduction / Chapter 1.1 --- Genus Cordyceps --- p.1 / Chapter 1.2 --- Cordyceps militaris --- p.4 / Chapter 1.3 --- Biological Functions and Chemical Constituents of Cordyceps militaris --- p.9 / Chapter 1.4 --- "Human Bronchial Epithelial Cell Line, 16HBE14o-" --- p.13 / Chapter 1.5 --- Ion Transport in Human Bronchial Epithelial Cells --- p.16 / Chapter 1.6 --- Objectives of the Experiments --- p.20 / Chapter Chapter 2 - --- Materials and Methods / Chapter 2.1 --- Solutions and Chemicals --- p.21 / Chapter 2.2 --- Preparation of Hot Water Cordyceps militaris Extract --- p.22 / Chapter 2.3 --- Culture of Cells --- p.23 / Chapter 2.4 --- Short-Circuit Current (lsc) Measurement --- p.24 / Chapter 2.5 --- Short-Circuit Current (lsc) Measurement in Nystatin-Permeabilized Monolayer --- p.29 / Chapter 2.6 --- Measurements of [Ca2+]i --- p.31 / Chapter 2.7 --- Measurement of PKA Activity --- p.36 / Chapter 2.8 --- Statistical Analysis --- p.37 / Chapter Chapter 3 - --- Results / Chapter 3.1 --- Regulation of Ion Transport in 16HBE14o- Cells by CM Water Extract --- p.38 / Chapter 3.1.1 --- Dose-Dependent Relationship of CM Water Extract --- p.39 / Chapter 3.1.2 --- "Involvement of CI"" Transport in CM-induced lsc Response" --- p.42 / Chapter 3.1.3 --- Involvement of K+ channels in CM-induced lsc Response --- p.47 / Chapter 3.1.4 --- Involvement of Adenylate Cyclase/cAMP/Protein Kinase A Pathway in CM-induced lsc Response --- p.52 / Chapter 3.1.5 --- Involvement of Ca2+-Dependent Pathway in CM-induced lsc Response --- p.57 / Chapter 3.1.6 --- "Effect of CM Extract on Apical CI"" Current and Basolateral K+ Current in Nystatin-Permeabilized Epithelia" --- p.61 / Chapter 3.1.7 --- Effect of CM Extract on PKA Activity --- p.67 / Chapter 3.2 --- Regulation of Ion Transport in 16HBE14o- Cells by Cordycepin --- p.70 / Chapter 3.2.1 --- Dose-Dependent Relationship of Cordycepin --- p.70 / Chapter 3.2.2 --- "Involvement of CI"" Transport in Cordycepin-induced lsc Response" --- p.73 / Chapter 3.2.3 --- Involvement of K+ channels in Cordycepin-induced lsc Response --- p.79 / Chapter 3.2.4 --- Involvement of Adenylate Cyclase/cAMP/Protein Kinase A Pathway in Cordycepin-induced lsc Response --- p.84 / Chapter 3.2.5 --- Involvement of Ca2+-Dependent Pathway in Cordycepin-induced lsc Response --- p.89 / Chapter 3.2.6 --- Effect of Cordycepin on Intracellular Ca2+ Concentrations --- p.93 / Chapter 3.2.7 --- "Effect of Cordycepin on Apical CI"" Current and Basolateral K+ Current in Nystatin-Permeabilized Epithelia" --- p.98 / Chapter 3.2.8 --- Effect of Cordycepin on PKA Activity --- p.104 / Chapter Chapter 4 - --- Discussion / Chapter 4.1 --- Regulation of Ion Transport in 16HBE14o- Cells by CM Extract --- p.107 / Chapter 4.2 --- Intracellular Signaling Mechanisms behind CM-induced lsc Responses --- p.110 / Chapter 4.3 --- Regulation of Ion Transport in 16HBE14o- Cells by Cordycepin --- p.111 / Chapter 4.4 --- Intracellular Signaling Mechanisms behind Cordycepin-induced lsc Responses --- p.114 / Chapter Chapter 5 - --- Conclusion / Chapter 5.1 --- Summary --- p.117 / Chapter 5.2 --- Future Directions --- p.120 / Chapter Chapter 6 - --- References --- p.121 / Chapter Chapter 7 - --- Publications --- p.136

By performing microRNA microarrays to globally detect any novel miRNAs in the limbus, eleven microRNAs (hsa-miR-136, hsa-miR-373*, hsa-miR-150, hsa-miR-143, hsa-miR-455, hsa-miR-145, hsa-miR-381, hsa-miR-224, hsa-miR-338, hsa-miR-154, hsa-miR-377) were found to be upregulated while two microRNAs (hsa-miR-122a and hsa-miR-425-3p) were identified as downregulated by more than 2 folds. Among these, hsa-miR-143 and hsa-miR-145 were distingushed to be the most significantly up-regulated limbal miRNAs. Individual assessement of the microarray results of a recently reported stem cell specific microRNA, hsa-miR-21, were also upregulated by more than two thousand fold when comparing limbus and cornea. miR-21, miR-143 and miR-145 were therefore selected as the most likely microRNA candidates in the present study. The expression level of these miRNA candidates were validated and confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). To localize these candidates, we performed in situ hybridization on frozen corneal rim sections using locked nucleic acid (LNA)-modified oligonucleotide probes. Results showed that miR-2I, 143 and 145 were confined in the limbal region with gradation of expression level along the basal-suprabasal line. / Functional roles of these microRNAs were then deciphered by overexpressing human corneal epithelial cell line (HCE) with precursor microRNAs (pre-miRs) through lipophilic transfection. Results showed that high endogenous level of miR-145 could inhibit cell proliferation by 3.5 fold as shown from MTT proliferation assay at day 5, and could generate discrete spherical colonies that resembles the morphology of holoclones at day 8, but not the other two candidate miRNAs. / In conclusion, 1 have identified three novel microRNAs (hsa-miR-21, 143, 145) which were precisely upregulated in the limbus region, while miR-145 was being the most limbal specific. In addition, the functions of miR-145 were found to be inhibitory on cell proliferation, possibly through the indirect regulation of IFNB1. These unprecedented results may suggest a therapeutic potential of miR-145 on limbal stem cell deficiency and limbal tumors because miR-145 can affect cell survival and proliferation. / MicroRNAs is a family of small non-coding RNAs that, in human, binds imperfectly to the 3' untranslated region (UTR) of target mRNAs for translational repression or negative regulation. Recent studies have shown that such negative regulatory pathways may play pivotal roles in the maintenance of asymmetric cell division in embryonic and tissue specific stem cells. Human corneal epithelial progenitor cells (CEPC), a tissue specific stem cell lineage residing between cornea and conjunctiva in the Palisade of Vogt of the limbus region, is known to maintain corneal homeostasis throughout human life. They respond to injury and normal wearing by rapid proliferation and differentiation into transit amplifying cells (TACs) and eventually corneal epithelial cells, though the biological factors controlling this homeostatic switch are still largely unknown. Here I hypothesized that microRNAs can participate in CEPC regulation. Experiments elucidating the anatomical distribution and functional roles of microRNAs on the human cornea rims were performed to testify this proposition. / Protocols aim at enriching the CEPC population were then devised. For the first time a four parameter cell sorting system utilizing ABCG2, Connexin 43, Notch 1 and pyronin Y as markers was established for the prospective in vitro study. Nevertheless, manual microdissection isolating the limbus region and the cornea region was employed for the present study of microRNAs. / This study begins with the phenotypic validation of human cornea rims recruited from the Chinese Hong Kong population using immunohistochemistry. Conventional CEPC markers (p63, EGFR, cytochrome oxidase and cytokeratin 15), embryonic stem cell marker (stat1) and cancer stem cell markers (p73, MDM2 and pStat1) were expressed in the limbus region, suggesting that these specimens contained a source of CEPC for attesting our hypothesis. / To determine the mRNA targets of candidate microRNAs in HCE cells, Whole Human Genome Oligo Microarray Kits (Agilent Technologies) which contained 41K human genes and transcripts were employed. When compared to the scrambled control, HCE cells over-expressed with hsa-miR-21, 143 or 145 revealed differential expression of genes that participate in cell activation, motility and proliferation. Of note, interferon beta 1 fibroblast (IFNB1), a gene that is often deleted or rearranged in cancers, was significantly upregulated by a medium of 1093 fold in pre-miR-145 treated cells as confirmed by real time PCR assays. / Lee, Sharon Ka-wai. / "December 2009." / Advisers: Calvin Chi-Pui Pang; Gary Hin Fai Yam. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 216-252). / 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.