Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Postmenopausal osteoporosis is a disease characterized by bone loss and increased risk of fracture, and represents a significant burden on the Canadian health care system. Current treatments lack the ability to simultaneously address the therapeutic needs for promoting bone formation and inhibiting resorption. Our approach employs a novel conjugate drug in which an anabolic agent (EP4 receptor agonist) is reversibly joined with an anti-resorptive agent (alendronate) through a linker. This allows the bone-targeting ability of alendronate to deliver the EP4 agonist to bone sites, thereby mitigating the side effects associated with systemic administration of the EP4 agonist. This study investigated the in vivo efficacy of this drug in a curative experiment to treat postmenopausal osteoporosis using an ovariectomized rat model. Results showed that conjugate treatment dose-dependently stimulated bone formation and restored ovariectomy-induced bone loss, and conjugation between alendronate and the EP4 agonist was crucial to the drug’s anabolic effect.

Postmenopausal osteoporosis is a disease characterized by bone loss and increased risk of fracture, and represents a significant burden on the Canadian health care system. Current treatments lack the ability to simultaneously address the therapeutic needs for promoting bone formation and inhibiting resorption. Our approach employs a novel conjugate drug in which an anabolic agent (EP4 receptor agonist) is reversibly joined with an anti-resorptive agent (alendronate) through a linker. This allows the bone-targeting ability of alendronate to deliver the EP4 agonist to bone sites, thereby mitigating the side effects associated with systemic administration of the EP4 agonist. This study investigated the in vivo efficacy of this drug in a curative experiment to treat postmenopausal osteoporosis using an ovariectomized rat model. Results showed that conjugate treatment dose-dependently stimulated bone formation and restored ovariectomy-induced bone loss, and conjugation between alendronate and the EP4 agonist was crucial to the drug’s anabolic effect.

The interplay between lipids and membrane proteins is known to affect membrane protein topology and thus have significant effect (control) on their functions. In this PhD thesis, the influence of lipids on the membrane protein function was studied using three different membrane protein models. A monotopic membrane protein, monoglucosyldiacylglyecerol synthase (MGS) from Acholeplasma laidlawii is known to induce intracellular vesicles when expressed in Escherichia coli. The mechanism leading to this unusual phenomenon was investigated by various biochemical and biophysical techniques. The results indicated a doubling of lipid synthesis in the cell, which was triggered by the selective binding of MGS to anionic lipids. Multivariate data analysis revealed a good correlation with MGS production. Furthermore, preferential anionic lipid sequestering by MGS was shown to induce a different fatty acid modeling of E. coli membranes. The roles of specific lipid binding and the probable mechanism leading to intracellular vesicle formation were also investigated. As a second model, a MGS homolog from Synechocystis sp. PCC6803 was selected. MgdA is an integral membrane protein with multiple transmembrane helices and a unique membrane topology. The influence of different type of lipids on MgdA activity was tested with different membrane fractions of Synechocystis. Results indicated a very distinct profile compared to Acholeplasma laidlawii MGS. SQDG, an anionic lipid was found to be the species of the membrane that increased the MgdA activity 7-fold whereas two other lipids (PG and PE) had only minor effects on MgdA. Additionally, a working model of MgdA for the biosynthesis and flow of sugar lipids between Synechocystis membranes was proposed. The last model system was another integral membrane protein with a distinct structure but also a different function. The envelope stress sensor, CpxA and its interaction with E. coli membranes were studied. CpxA autophosphorylation activity was found to be positively regulated by phosphatidylethanolamine and negatively by anionic lipids. In contrast, phosphorylation of CpxR by CpxA revealed to be increased with PG but inhibited by CL. Non-bilayer lipids had a negative impact on CpxA phosphotransfer activity. Taken together, these studies provide a better understanding of the significance of the interplay of lipids and model membrane proteins discussed here.

It is evident that components of the 26S proteasome function beyond protein degradation in the regulation of transcription. Studies in yeast implicate the 26S proteasome, specifically the 19S cap, in the epigenetic regulation of transcription. Saccharomyces cerevisiae 19S ATPases remodel chromatin by facilitating histone acetylation and methylation. However, it is unclear if the 19S ATPases play similar roles in mammalian cells. We previously found that the 19S ATPase Sug1 positively regulates transcription of the critical inflammatory gene MHC-II and that the MHC-II promoter fails to efficiently bind transcription factors upon Sug1 knockdown. MHC-II transcription is regulated by the critical coactivator CIITA. We now find that Sug1 is crucial for regulating histone H3 acetylation at the cytokine inducible MHC-II and CIITA promoters. Histone H3 acetylation is dramatically decreased upon Sug1 knockdown with a preferential loss occurring at lysine 18. Research in yeast indicates that the ortholog of Sug1, Rpt6, acts as a mediator between the activating modifications of histone H2B ubiquitination and H3 methylation. Therefore, we characterized the role the 19S proteasome plays in regulating additional activating modifications. As with acetylation, Sug1 is necessary for proper histone H3K4 and H3R17 methylation at cytokine inducible promoters. In the absence of Sug1, histone H3K4me3 and H3R17me2 are substantially inhibited. Our observation that the loss of Sug1 has no significant effect on H3K36me3 implies that Sug1’s regulation of histone modifications is localized to promoter regions as H3K4me3 but not H3K36me3 is clustered around gene promoters. Here we show that multiple H3K4 histone methyltransferase subunits bind constitutively to the inducible MHC-II and CIITA promoters and that over-expressing one subunit significantly enhances promoter activity. Furthermore, we identified a critical subunit of the H3K4 methyltransferase complex that binds multiple histone modifying enzymes, but fails to bind the CIITA promoter in the absence of Sug1, implicating Sug1 in recruiting multi-enzyme complexes responsible for initiating transcription. Finally, Sug1 knockdown maintains gene silencing as elevated levels of H3K27 trimethylation are observed upon Sug1 knockdown. Together these studies strongly implicate the 19S proteasome in mediating the initial reorganization events to relax the repressive chromatin structure surrounding inducible genes.

This study has examined opportunities for reclaiming industrial brownfield sites for the communities that surround them, recreating derelict sites as community-oriented spaces that increase understanding of and restore pride in industrial and cultural heritage.The study consisted of two primary components. The first phase consists primarily of an exploration of the linkages between landscape/urban design and industrial heritage. This phase also examines and evaluates various design projects that have attempted to celebrate industrial heritage through the adaptive re-use of former industrial sites. The second phase of the study consists of the development of a master plan for the transformation of a derelict industrial site to a community space that interprets and celebrates industrial heritage. This phase includes researching the industrial heritage of Muncie, selecting an appropriate project site within the city, and developing a master plan for the reclamation of an industrial site by the community.A layered design strategy was developed for the selected site, with the end result being a master plan for a new public park. The three elements of the design strategy included industrial heritage, adaptive reuse, and improvements in the surrounding community. / Department of Landscape Architecture

The structure now owned by Redeemer Presbyterian Church in Indianapolis, IN was built in 1903 at 16th and Delaware Streets by a very prominent congregation, the First Presbyterian Church. Since its construction, the building has been subject to a rehabilitation that destroyed many historic features of the building, followed by abandonment that led to its overall deterioration. For the past four years the building has been occupied once again following a partial rehabilitation.This study found that the building was historically intact on the exterior, but problems such as the deterioration of the limestone were threatening the overall integrity of the structure. The interior, which had been subject to many alterations as part of a 1958 renovation, was fully functional and in good condition but was missing many historic features.This study makes recommendations for repairs on the exterior and an interior rehabilitation that restores some missing historic features, and promotes the retention and stewardship of the existing historic features within the building. / Department of Architecture

The purpose of this thesis is to assess the characteristics and aspects that make B&Bs, particularly historic B&Bs, successful. This thesis also briefly demonstrates how historic B&Bs can contribute to communities and to the field of historic preservation through public awareness and adaptive reuse projects. Background information on the B&B industry is presented. Sources for the research include B&B owners, professionals in the B&B industry and historic preservation fields, written sources, and studies conducted on B&B owners and their businesses. Six B&Bs and their owners were selected as case studies in Indiana. Four of these six B&Bs were included in a previous Ball State thesis, The Role of Bed and Breakfasts in Heritage Tourism, prepared by Terri Ash in 1996.Additionally, three case studies in Georgia were chosen to increase diversity in the types of B&Bs evaluated. A profile of each B&B is presented; it includes information on the history of the B&B, why the owners decided to open up the B&B, the type of rehabilitation work that was needed, and how, if applicable, the B&B has changed over the last ten years. All of the information gathered from primary and secondary sources is combined to form conclusions regarding the primary aspects and common characteristics that contribute to a successful B&B. Primary conclusions drawn from this study include how the location, the number of rooms, the amenities, and the hospitality of the owners contribute to a successful B&B. Additionally, conclusions are drawn that compare the likelihood of success between historic B&Bs to non-historic B&Bs, and the benefits of locating a B&B in a historic building. / Department of Architecture

The housing estates boom was and is a result of the Southeast Asia economic growth after the economic crisis between 1997 and 1998. Housing estates, especially in the suburbs of Bangkok, are designed by considering only aesthetics and costs without considering the negative effects that might occur to the occupants and nature. These negative effects lead to the insufficiency energy crisis.Determining how to reduce the energy used and increase the living quality in the building type is the critical question for architects to answer. Redesigning the housing estate using sustainable design concepts, especially with a focus on the natural ventilation and shading device strategies, can lift up the occupants' living quality because such design can provide cross ventilation through the house and solar shading to reduce the heat gain in the house. Not only would such design improvements make houses more comfortable for inhabitants, they also would reduce the energy use.The methodologies of research start with spatial analyses to define the general character of this type of house, then the redesigning of a selected existing house is used to focus on natural ventilation and shading devices design in order to improve the occupants living quality and to reduce the energy used in the house. It is hoped that this project can be the first step for other architects to understand the logic of natural ventilation and shading control design strategies within the realm of sustainability. / Department of Architecture

The human genome project has allowed for the rapid identification of a large number of protein families based on similarities in their genetic sequences. The acyl-glycerol phosphate acyltransferase (AGPAT) family of enzymes have been largely identified through sequence homology, with eleven isoforms identified in both mice and humans. Interestingly, very little work has been done on the characterization of AGPAT isoform 4. In the present study, I report the functional characterization of AGPAT4 as an acyl-CoA: lysocardiolipin acyltransferase (ALCAT), which we have renamed ALCAT2. Although ALCAT2 is present in most tissues, it is abundant in multiple brain regions including olfactory bulbs, hippocampus, cerebellum, cortex, and brain stem, and is detectable in both primary neurons and glial cells. In assays performed in vitro, ALCAT2 significantly increased the incorporation of [14C]oleoyl-CoA into phosphatidylinositol and CL using either lysophosphatidylinositol, or monolysocardiolipin or dilysocardiolipin as acyl acceptors, respectively. ALCAT2 did not display significant acyltransferase activity with lysophosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylserine, or lysophosphatidylglycerol acyl acceptors. Overexpressing ALCAT2 in HEK-293 cells increased the total CL content, but did not significantly affect levels of other glycerophospholipids including phosphatidylinositol. Analysis of the fatty acyl profile of CL from ALCAT2-overexpressing cells indicated increased total saturated fatty acids, particularly stearate, palmitate, and myristate, and increased levels of n-3 polyunsaturated fatty acids α-linolenic acid (18:3n-3), eicosatrienoic acid (20:3n-3), and eicosapentanoic acid (20:5n-3). In accordance with its observed role in cardiolipin remodeling, ALCAT2 localized predominately to the mitochondria. ALCAT2 was also regulated during embryogenesis, and in varying metabolic states. In summary, ALCAT2 is a new enzyme in CL remodeling with a potential role in mitochondrial function.