Introduction: Many people living with HIV/AIDS (PLHIV) in Uganda widely use herbal medicines. However, their toxicity and safety have not been investigated. The use of these plants can potentially cause harmful effects to the health of patients. The purpose of this study was to determine the cytotoxicity of some commonly used medicinal plant species used by PLHIV. Methods: The cytotoxicity of the plant extracts was determined with the AlamarBlue cell viability assay using the human glioblastoma cell line U87.CD4.CXCR4. The cells were treated with varying concentrations of extracts of Warburgia ugandensis, Erythrina abyssinica, Cryptolepis sanguinolenta, Albizia coriaria, Psorospermum febrifugium, Gymnosporia senegalensis, Zanthoxylum chalybeum, Securidaca longipendunculata, Vachellia hockii, Gardenia ternifolia, and Bridelia micrantha reconstituted with ethanol and dimethyl sulfoxide (DMSO). Using regression analysis, the half maximal cytotoxic concentration (CC50) of the plant extracts were calculated from exponential curve fits, since they provided the highest coefficient of determination, R2. Results: The ethanol extracts of W. ugandensis (CC50 = 7.6 μg/ml) and A. coriaria (CC50 = 1.5 μg/ml) as well as the DMSO-reconstituted extracts of W. ugandensis (CC50 = 6.4 μg/ml) and A. coriria (CC50 = < 4 μg/ml) were highly cytotoxic. The cytotoxicity of W. ugandensis and A. coriaria compared well with the indigenous traditional knowledge of the toxic effects experienced when the plants were not used correctly. However, the cytotoxicity of most of the plant extracts (15/22) was low to moderate (CC50 = 21-200 μg/ml). Conclusion: Most of the plant species tested in this study had low to moderate cytotoxicity against U87.CD4.CXCR4 cells, except W. ugandensis and A. coriria which were highly cytotoxic.

Herbs have been used for many centuries in diverse civilizations for the treatment of heart disease. Only a few natural supplements claim to have direct cardiovascular actions including hawthorn (Crataegus spp.) and berberine derived from the Berberidaceae family. Several different studies indicate important cardiovascular effects of hawthorn and berberine. For example, both exert positive inotropic effects and have been used in the treatment of congestive heart failure. Recently, it was shown that hawthorn extract preparations cause negative chronotropic effects in a cultured neonatal murine cardiomyocyte assay independent of beta-adrenergic receptor blockade. The aim of this study was to further characterize the effect of hawthorn extract to decrease the contraction rate of cultured cardiomyocytes. We hypothesized that hawthorn extract may be acting through muscarinic receptors to decrease contraction rate of cardiomyocytes. Atrial and ventricular cardiomyocytes were treated with hawthorn extract in the presence of atropine or himbacine. Changes in the contraction rate of cultured cardiomyocytes revealed that both muscarinic antagonists significantly attenuated the negative chronotropic activity of hawthorn extract. Using quinuclidinyl benzilate, L-[benzylic-4,4'-3H] ([³H]-QNB) as a radioligand antagonist, the effect of a partially purified hawthorn extract fraction to inhibit muscarinic receptor binding was quantified. Hawthorn extract fraction 3 dose-dependently inhibited [³H]-QNB binding to mouse heart membranes. These findings suggest that muscarinic receptors may be involved in the negative chronotropic effect of hawthorn extracts in neonatal murine cardiomyocytes. Berberine exhibits variable positive and negative chronotropic effects in different species. Our first aim was to examine the effect of berberine in a cultured neonatal murine cardiomyocyte assay. Our study demonstrates that berberine has significant negative chronotropic actions on cardiomyocytes which is not an effect of beta-adrenergic receptor blockade. Pertussis toxin (PTX), a Gi/o protein inhibitor, blocked the negative chronotropic activity of berberine. Muscarinic, adenosine, opioid, and α₂ receptors are coupled through a G-protein (Gi/o) to adenylyl cyclase in an inhibitory fashion. Activation of these receptors are primarily responsible for PTX-sensitive negative chronotropic effects in heart. We hypothesized that berberine may be acting through one of these receptor type to decrease contraction rate of cardiomyocytes. For this purpose, we studied the effects of the muscarinic-receptor antagonists, atropine, himbacine, or AF- DX 116 on the negative chronotropic activity of berberine. Muscarinic antagonists completely blocked the effect of berberine on contraction rate of cardiomyocytes, whereas the bradycardic effect of berberine was not inhibited by the opioid, adenosine, or α2 receptor antagonists naloxone, CGS 15943, or phentolamine, respectively. Using [³H]QNB as a radioligand, we demonstrated that berberine bound to muscarinic receptors of adult mouse heart membranes with relatively high affinity. Furthermore, berberine dose-dependently inhibited [³H]QNB binding to muscarinic M2 receptors exogenously expressed in HEK 293 cells. Therefore, the findings of the present study suggest that berberine has muscarinic agonist effects in cultured neonatal murine cardiomyocytes, potentially explaining reported physiological effects of berberine. Cardiac hypertrophy represents the most important factor in the development of congestive heart failure. We investigated the inhibitory effect of berberine on hypertrophy of H9c2 cells. In rat heart-derived H9c2 myoblast cells treated with different hypertrophic agonists such as insulin growth factor II (IGF-II), arginine vasopressin (AVP), phenylephrine, and isoproterenol, protein content and size of cells were significantly increased compared to control group. However, the number of H9c2 cells after treatment with hypertrophic agonists did not differ significantly compared to control. The increases in area of cells and protein content induced by the hypertrophic agonists were inhibited by treatment with berberine in a concentration-dependent manner. Our findings have provided the first scientific evidence that berberine may have an inhibitory effect on hypertrophy of heart-derived cells, and provide a rationale for further studies to evaluate berberine's cardiac activity. / Graduation date: 2010

The mammalian protein POT1 binds to telomeric single-stranded DNA (ssDNA), protecting chromosome ends from being detected as sites of DNA damage. POT1 is composed of an N-terminal ssDNA-binding domain and a C-terminal protein interaction domain. With regard to the latter, POT1 heterodimerizes with the protein TPP1 to foster binding to telomeric ssDNA in vitro and binds the telomeric double-stranded-DNA-binding protein TRF2. We sought to determine which of these functions-ssDNA, TPP1, or TRF2 binding-was required to protect chromosome ends from being detected as DNA damage. Using separation-of-function POT1 mutants deficient in one of these three activities, we found that binding to TRF2 is dispensable for protecting telomeres but fosters robust loading of POT1 onto telomeric chromatin. Furthermore, we found that the telomeric ssDNA-binding activity and binding to TPP1 are required in cis for POT1 to protect telomeres. Mechanistically, binding of POT1 to telomeric ssDNA and association with TPP1 inhibit the localization of RPA, which can function as a DNA damage sensor, to telomeres. / Dissertation

The main source of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) in our diet is supplied by fish, and an ever-increasing proportion of these are being produced by aquaculture. The drive for the growing market demand and production from sustainable sources has led to the use of high-energy (fat) diets and, recently, to the replacement of fishmeal and fish oil with non-marine components, such as plant meals and vegetable oils that are devoid of n-3 LC-PUFA. Both changes impact greatly on lipid and fatty acid metabolism in fish, with health implications for the fish and the human consumer. This impact highlights the need to investigate the basic molecular mechanisms underlying the regulation of lipid and fatty acid metabolism in fish, specifically focussing on the pathways of lipid homeostasis and LC-PUFA synthesis. The aim of this study was to develop and utilise Chinook salmon embryo (CHSE-214) cell line as a model for Atlantic salmon, Salmo salar L., to enable an integrated approach to study the biochemical and molecular regulation of lipid metabolism in fish. In particular, α-linolenic acid (LNA, 18:3n-3) and linoleic acid (LOA, 18:2n-6), which are essential fatty acids abundantly found in vegetable oils, and are precursors of LC-PUFA, were supplemented in combination with other fatty acids, to explore the effect of these on total lipid content, lipid class, FA composition and gene expression of CHSE-214 cell line. Total lipid content was extracted, followed by determination of lipid class and fatty acid analyses. Gene expression analyses of transcription/nuclear factors and various target genes in Atlantic salmon, including those involved in pathways of LC-PUFA synthesis and fatty acid oxidation, were carried out. The results demonstrated that CHSE-214 cell line, under experimental conditions, is able to convert LNA to eicosapentaenoic acid (EPA, 20:5n-3), and LOA to arachidonic acid (ARA, 20:4n-6), but not LNA and/or EPA to docosahexaenoic acid (DHA, 22:6n-3), highlighting the activity of elongase and desaturase enzymes during the conversion process. Changes occurring on the fatty acid profile and also at molecular level were observed. Understanding the role that transcription factors play in the regulation of lipid biosynthesis in fish will allow endogenous LC-PUFA synthesis to be optimised. The results from this study could be used to improve the efficiency of alternative, sustainable diets in aquaculture, while maintaining the nutritional quality of farmed fish for the final consumer. CHSE-214 cell line can therefore be used as a model to study the molecular mechanisms involved in the LC-PUFA biosynthesis, particularly in the conversion of LNA to EPA, which can then be reproduced in vivo, saving time and money.

L’adénovirus possède plusieurs caractéristiques faisant de ce virus un candidat de choix pour la construction de vecteurs utiles dans les études de génomique fonctionnelle. Dans la majorité de ces applications, on a recours à un vecteur adénoviral de première génération délété de sa région E1. L’utilisation de vecteurs adénoviraux comprend deux maillons faibles : la construction du vecteur et la production subséquente de ce dernier. Le développement de méthodes alternatives est donc nécessaire pour renforcer ces deux maillons, permettant ainsi une utilisation étendue de ces vecteurs. Ce développement va s’articuler sur deux axes : l’ingénierie du vecteur de transfert pour la construction de l’adénovirus recombinant et l’ingénierie d’une lignée cellulaire pour la production du vecteur. En utilisant un vecteur de transfert adénoviral co-exprimant, à partir d’un promoteur régulable à la tétracycline, la protéase de l’adénovirus et une protéine de fluorescence verte (GFP) par l’intermédiaire d’un site d’entrée ribosomal interne (IRES), notre groupe a établi que la sélection positive, via l’expression ectopique de la protéase, est un processus efficace pour la création de librairie d’adénovirus recombinants. Par contre, la diversité atteinte dans ce premier système est relativement faible, environ 1 adénovirus recombinant par 1 000 cellules. Le travail effectué dans le cadre de cette thèse vise à construire un nouveau transfert de vecteur dans lequel l’expression de la protéase sera indépendante de celle du transgène permettant ainsi d’optimiser l’expression de la protéase. Ce travail d’optimisation a permis de réduire le phénomène de transcomplémentation du virus parental ce qui a fait grimper la diversité à 1 virus recombinant par 75 cellules. Ce système a été mis à l’épreuve en générerant une librairie adénovirale antisens dirigée contre la GFP. La diversité de cette librairie a été suffisante pour sélectionner un antisens réduisant de 75% l’expression de la GFP. L’amplification de ce vecteur adénoviral de première génération doit se faire dans une lignée cellulaire exprimant la région E1 telle que les cellules 293. Par contre, un adénovirus de première génération se répliquant dans les cellules 293 peut échanger, par recombinaison homologue, son transgène avec la région E1 de la cellule créant ainsi un adénovirus recombinant réplicatif (RCA), compromettant ainsi la pureté des stocks. Notre groupe a déjà breveté une lignée cellulaire A549 (BMAdE1) exprimant la région E1, mais qui ne peut pas recombiner avec le transgène du virus. Par contre, le niveau de réplication de l’adénovirus dans les BMAdE1 est sous-optimal, à peine 15-30% du niveau obtenu dans les cellules 293. Le travail fait dans le cadre de cette thèse a permis de mettre en évidence qu’une expression insuffisante d’E1B-55K était responsable de la mauvaise réplication du virus dans les BMAdE1. Nous avons produit de nouveaux clones à partir de la lignée parentale via une transduction avec un vecteur lentiviral exprimant E1B-55K. Nous avons confirmé que certains clones exprimaient une plus grande quantité d’E1B-55K et que ces clones amplifiaient de manière plus efficace un vecteur adénoviral de première génération. Ce clone a par la suite été adapté à la culture en suspension sans sérum. / The adenovirus has numerous interesting characteristics making this particular virus an ideal candidate for the construction of vector for conducting studies in functional genomics. The vast majority of those applications rely on a so-called “first-generation vector” in which the E1 region is replaced by a transgene. Despite all their advantages, there are 2 weak links associated with first-generation vector: the efficient construction of the actual vector and its production. Therefore, the development of alternative methods for construction and production is necessary to ensure their usefulness. The development will involve 2 axes: the reengineering of the transfer vector for the construction of recombinant adenovirus and the reengineering of the cell line capable of producing the vector. Using a transfer vector co-expressing the adenoviral protease (PS) gene and GFP by using an IRES under the control of a tetracycline-regulated promoter, our laboratory previously established the proof of concept that positive selection of recombinant adenovirus through ectopic expression of the PS gene was an efficient approach to generate adenoviral libraries. However, the diversity achieved was quite low, around 1 recombinant adenovirus per 1,000 cells. The goal of this thesis was to design a new transfer vector in which the PS expression was independent from the expression of the transgene in order to be able to optimize its expression independently. We also improved library diversity by lowering the amount of PS in order to reduce the the trans-complementation from the transfer vector. Using this method, at least 1 recombinant adenovirus per 75 cells was generated with 100% of the plaques being recombinant. This system was successfully used to generate an antisense library targeting GFP. The diversity of the library was high enough to allow the selection of an antisense that inhibited 75% of GFP expression. Amplification of those first-generation recombinant adenoviruses must take place in an E1-expressing cell such as 293 cells. However, when replicating in 293 cells, the recombinant adenovirus can exchange their transgene with the E1 region of the cell by homologous recombination, which results in the generation of a fully replicative adenovirus (RCA), a situation that compromises the purity of the viral preparation. Our laboratory has previously patented an A549 cell line expressing the E1 region and producing RCA-free recombinant adenovirus (BMAdE1). However, the replication of E1-deleted adenovirus in BMAdE1 cells was sub-optimal, in the range of 15-30% the level obtained in 293 cells. The work done in this thesis establishes that the low level of E1B-55K could be responsible for the lower productivity of BMAdE1 cells. Thus, we have derived new clones following lentiviral transduction in order to increase E1B-55K expression. Western blot confirmed that some clones expressed more E1B-55K than BMAdE1, and this correlated with a more robust replication of a recombinant adenovirus in those clones. This newly optimized BMAdE1 cell line was adapted to serum-free suspension culture.

A Terapia Fotodinâmica (TFD) é um tratamento usado principalmente na terapia anticâncer e que depende da retenção de um composto fotossensibilizante nas células tumorais e posterior irradiação dessas células com luz visível. Após ativação, o fármaco pode gerar espécies reativas de oxigênio (EROs), como o oxigênio singlete (1O2) e radicais (O2-, OH), que são capazes de danificar membranas, DNA e outras estruturas celulares, induzindo a apoptose ou necrose das células tumorais. O ácido fólico, por ser super expressado na superfície das células de alguns tipos de cânceres (principalmente os ginecológicos), pode desempenhar o papel de vetorizador, tornando-se um importante aliado aos sistemas de liberação de fármacos. Neste trabalho foi avaliado o uso de ácido fólico como aditivo aos lipossomas contendo ftalocianina de cloro-alumínio como fármaco fotossensibilizante, aplicados em TFD com células MCF7. Os estudos demonstraram que os sistemas lipossomais desenvolvidos apresentam tamanho nanométrico (menor que 200 nm) e possuem biocompatibilidade quando avaliados em cultura celular de monocamada. Além disso, foi possível observar o efeito fototóxico satisfatório das formulações e o aumento da internalização do fármaco, quando utilizado o ácido fólico como vetorizador. / Photodynamic Therapy (PDT) is mainly used in anticancer therapy. The efficiency of this treatment is dependent on retention of photosensitizer compound at the tumor cells and posterior irradiation of these cells with visible light. After activation, the drug may generate reactive oxygen species (ROS) such as singlet oxygen (1O2) and radicals (O2-, OH), which are capable of damaging membranes, DNA and other cell structures, inducing apoptosis or necrosis of tumor cells. Folic acid is super-expressed on the surface of some cancers cells (especially gynecological cancer cells) and can play the role of target system, becoming an important ally for drug delivery systems. This study evaluated the use of folic acid as an additive to liposomes containing chloro-aluminum phthalocyanine as a photosensitizer drug, applied in PDT with MCF7 cells. These studies showed that liposomal systems have nanometer size (less than 200 nm) and have biocompatibility when evaluated in monolayer cell culture. Moreover, it was possible to observe satisfactory phototoxic effect of the formulations and increased internalization of the drug when folic acid is used.

Mieloma Múltiplo é a segunda doença com maior prevalência nas doenças malignidades hematológica, incurável com média de sobrevivência de 3-5 anos. MM é uma malignidade das células do plasma caracterizada pela destruição e reabsorção óssea e supressão da formação do osso. A quimiocina SDF-1 (CXCL12) e seu receptor CXCR4 têm um importante papel direcional na migração, homing das células do plasma em mieloma múltiplo e mobilização das células de MM para fora da medula óssea. A talidomida tem sido usada com êxito no tratamento de pacientes com mieloma múltiplo. Neste estudo verificamos o efeito da talidomida na expressão da quimiocina SDF-1 e seu receptor CXCR4 em pacientes com mieloma múltiplo e em linhagem de células de mieloma múltiplo humano (RPMI-8226) tratados e sem tratamento de talidomida. Nossos resultamos mostraram uma expressão heterogênea na expressão da quimiocina SDF-1 e seu receptor CXCR4 nos pacientes com mieloma múltiplo estudado (n= 79). Entretanto, pacientes com mieloma múltiplo tratados com talidomida mostraram uma baixa expressão da quimiocina SDF-1 e seu receptor CXC4 quando comparados com pacientes recém diagnosticados para mieloma múltiplo e pacientes com mieloma múltiplo tratados com outros medicamentos. Nossos resultados sugerem que o tratamento com talidomida induz uma baixa regulação na expressão no ligante SDF-1 e seu receptor CXCR4 em pacientes com mieloma múltiplo / Multiple Myeloma (MM) is a second most prevalent hematological malignancy and remains incurable with a median survival of 3-5 years. MM is a plasma cell malignancy characterized by devastating bone destruction due to the enhanced bone resorption and suppressed bone formation. The chemokine stromal-derived factor-1 (SDF-1) and its receptor CXCR4 play an important role in directional migration, homing of plasma cells in multiple myeloma (MM) and mobilization of MM cells out of the bone marrow. The drug thalidomide has been successfully used in the treatment of patients with MM. In this study, we assessed the effect of thalidomide on SDF-1 and CXCR4 expression in MM patients and human myeloma-derived cell line, RPMI 8226 treated with or without thalidomide. A heterogeneous expression pattern of chemokines SDF-1 and CXCR4 receptor were observed for all MM patients studied. However, patients treated with thalidomide showed a significantly decrease in expression of SDF-1 and CXCR4 as compared to newly diagnosed MM patients and MM patients treated with other drugs. RPMI 8226 cell line treated with 10, 20 and 100µM thalidomide also demonstrated decrease in SDF-1 and CXCR4 expression as compared with cell control (RPMI-8226 without thalidomide). Ours results indicate that thalidomide therapy induces down-regulation of CXCR4 and its ligand SDF-1 in multiple myeloma

O objetivo do projeto foi desenvolver linhagens celulares para um anticorpo terapêutico anti-hTNF&#945; e comprovar sua funcionalidade. Os genes anti-hTNF&#945; foram clonados em células CHO para seleção da população estável mista, demonstrando expressão de anticorpo com reconhecimento de hTNF&#945; em estrutura tridimensional. A população de transfectantes de maior produtividade específica foi escolhida para geração de linhagem monoclonal utilizando a tecnologia robótica ClonePix FL. Não houve diferença estatística entre o anti-hTNF&#945; purificado e o produto de referência na cinética de ligação ao TNF&#945; e reconhecimento diferencial por Fc&#947;Rs em ensaios por SPR O ensaio de atividade funcional mostrou que o anti-TNF&#945; desenvolvido pôde neutralizar a citotoxicidade induzida em células L929 e inibir a expressão de ELAM-1 em HUVEC. Os resultados finais permitiram identificar os três melhores clones, estáveis por 60 gerações. A comparabilidade entre o anti-TNF&#945; desenvolvido e a referência permite admiti-lo como não inferior, um dos requisitos para o desenvolvimento de biossimilar. / The aim of the project was to develop a therapeutic anti-hTNF&#945; antibody and evaluate its functionality. The anti-hTNF&#945; synthezised genes were cloned into CHO cells and stable pools were selected, producing antibodies able to hTNF&#945; three-dimensional structure recognition. The stable pools displaying higher antibody yields were the source for the generation of monoclonal lineage by ClonePix FL robotic technology. The clones selection proceeded using different criteria as cell density, specific productivity, fed-batch performance, kinetics measured by surface plasmonic resonance, hTNF&#945; binding through ELISA, western-blotting and SPR, Fc&#947;Rs binding by SPR. Besides, a small number of clones was tested in functional assays by the impairment of cytotoxicity of hTNF&#945; over L929 cells and the inhibition of ELAM-1 expression by HUVEC. The long term stability testing allowed to finally select 3 top clones, not inferior to adalimumab reference by the above criteria.

Modelos humanizados de porco são muito importantes para pesquisa biomédica e desenvolvimento de novas drogas e tratamentos. Além de ser um melhor modelo para doenças humanas do que animais de menor porte devido sua maior semelhança fisiológica, anatômica, de metabolismo e tempo de vida, o modelo suíno ainda permite suprimento ilimitado de órgãos para transplante. Apesar dessas vantagens, a expressão gênica inconsistente de animais transgênicos tornam a criação e avaliação desses animais muito dispendiosas, imprevisível e não permite a comparação de resultados de animais diferentes de maneira apropriada. Nesse estudo descrevemos uma nova técnica utilizando o promoter endógeno para a geração de um protocolo de substituição de genes com padrão clonal (transplante clonal de genes) sem clonagem de células, preservando a expressão genética e sua regulação intactas. Esse protocolo é reprodutível e pode ser aplicado para mais de um alvo genético, permitindo geração rápida de linhas transgênicas de animais (14-20 dias) com potencial de se tornar o novo padrão para geração de animais transgênicos de grande porte Suínos / Humanized pig models are very important for biomedical research, and drugs and treatment development. Not only it is a better model for diseases than smaller animals because of its closer physiology, anatomy, metabolism and life span, it also may provide unlimited organs for transplantation. In spite of all this advantages, inconsistent gene expression in transgenic animals make its generation and evaluation expensive, unpredictable and do not allow proper outcome comparison between different animals. In this report we describe a reproducible technique utilizing the endogenous promoter for generation of a clonal pattern gene replacement protocol (clonal gene transplant) without cell cloning, maintaining the normal gene expression and its regulation. This protocol is reproducible and applicable to more than one gene target, allowing fast generation of transgenic animals cell lines (as low as 14-20 days) and could become the new standard for transgenic large animal generation

Zhu, Jinyong. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 128-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.