Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies against self-antigens. SLE has a complex multifactorial genetic basis. Genome wide association studies (GWAS) have implicated polymorphisms causing decreased expression in many genes in SLE etiology and will likely continue to implicate new genes. Therefore, the aim of my project was to create a modular system where the effect of knocking down a gene of interest can be studied in cell culture in a timely manner. This was accomplished by inserting shRNAmirs targeting our validation gene, A20, into a retroviral vector, creating viral particles using a packaging cell line, and infecting cultured cells. Two shRNAmirs were determined to be effective by qRT-PCR and Western blots on infected cells. Vectors carrying these shRNAmirs were used to infect ex vivo B cells and BMDCs, and results suggested that A20 knockdown may mediate functional changes in both cell types.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies against self-antigens. SLE has a complex multifactorial genetic basis. Genome wide association studies (GWAS) have implicated polymorphisms causing decreased expression in many genes in SLE etiology and will likely continue to implicate new genes. Therefore, the aim of my project was to create a modular system where the effect of knocking down a gene of interest can be studied in cell culture in a timely manner. This was accomplished by inserting shRNAmirs targeting our validation gene, A20, into a retroviral vector, creating viral particles using a packaging cell line, and infecting cultured cells. Two shRNAmirs were determined to be effective by qRT-PCR and Western blots on infected cells. Vectors carrying these shRNAmirs were used to infect ex vivo B cells and BMDCs, and results suggested that A20 knockdown may mediate functional changes in both cell types.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available online.

Thesis (M. Phil.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 108-130).

No description available.

>Magister Scientiae - MSc / Systemic lupus erythematosus is a chronic, inflammatory disease characterised by the production of autoantibodies which target particularly the nuclear components of multiple cell types throughout the body. MicroRNA’s have been well-established to regulate gene function by partial-, or complete binding to the 3’-UTR of the target genes, causing repression or complete degradation of the target gene. As a result, proteins normally produced by the targeted mRNA would exhibit a decrease in production.The aim of this study was to investigate the interactions between genes and microRNAs implicated in the pathogenesis of SLE. Objectives included curating lists of miRNAs and genes associated with lupus pathogenesis, to identify regulatory targets of miRNAs and genes targeted by miRNAs, and to find the intersections of these outputs. By examining the intersections of the resultant targets, we aimed to identify novel interactions using Pathway Analysis, which have not been previously reported in scientific literature, to be associated with the pathogenesis of SLE. Understanding the miRNA-gene target interactions in the progression of SLE may provide us with essential biomarkers and targets for disease diagnosis and therapy. / National Research Foundation (NRF) and DAAD

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production and deposition of nuclear self-antigen-containing immune complexes. Epigenetic factors, including altered microRNA (miRNA) expression, may contribute to aberrant immune cell function in SLE. miRNAs are small, noncoding RNAs that bind to the 3’ untranslated region of target mRNAs resulting in post-transcriptional gene modulation. IL-6, an inflammatory cytokine overproduced by mesangial cells in SLE, contains a potential binding site for miR-let-7a. In order to examine if alterations in miR-let-7a expression can influence inflammatory mediator production in SLE, we isolated mesangial cell miRNAs from 8 and 32- week-old female New Zealand Black/White (NZB/W) mice. We found miR-let-7a expression was significantly increased in the mesangial cells of pre-diseased and actively diseased NZB/W mice compared to age-matched female New Zealand White (NZW) controls. Overexpression of miR-let-7a in vitro increased IL-6 production in LPS/IFN-γ-stimulated mesangial cells compared to the stimulated control. Due to the crucial role of miR-let-7a in cell division and inflammation, we investigated miR-let-7a-mediated proliferation and NFκB activation in J774A.1 macrophages and MES 13 mesangial cells in vitro. Cell proliferation, retinoblastoma protein (Rb) phosphorylation, and NFκB activation were increased in cells transfected with miR-let-7a and stimulated with LPS/IFN-γ. Expression and production of the cell cycle inhibitor E2F5 was decreased in stimulated cells overexpressing miR-let-7a. We found that the cell cycle promoter E2F2 and NFκB target the miR-let-7a promoter. Next we sought to determine alterations in iii specific disease-associated miRNAs in female NZB/W mice treated with hydroxychloroquine (HCQ) or prednisone (PRED) for 12 weeks beginning at 20 weeks-of-age. We found that treatment with HCQ or PRED induced unique changes to miRNA expression in multiple tissues. In order to identify specific miRNAs as disease-modifying agents and not merely disease correlates, further in vitro analyses confirmed HCQ or PRED-mediated inhibition of miRNAs is critical to alter the inflammatory response. Taken together, our results suggest that overexpression of miR-let-7a may contribute to hyperplasia and the proinflammatory response in SLE. Our studies indicate that lupus therapeutics may work, in part, by altering the expression of disease-associated miRNAs in immune cells and the urine. / Ph. D.

The major pathologic feature of the human autoimmune disease Systemic Lupus Erythematosus (SLE) and its murine counterpart, murine lupus, is the production of autoantibodies to nucleic acid antigens. In this study, a panel of six murine monoclonal anti-DNA autoantibodies was characterized at both the cellular and molecular levels in order to determine their possible role in the etiology of autoimmune disease. At the cellular level the autoantibodies were found to be highly cross-reactive, binding to three different antigenic forms of DNA as well as to the cell surface of various lymphoid cell lines. Furthermore, the fact that this autoantibody binding could be abrogated by pretreating the cells with either Proteinase K or DNase supports the hypothesis that a DNA binding protein may exist on the cell surface and that DNA bound to this receptor may serve as the target for the anti-DNA autoantibody. At the molecular level, the immunoglobulin (Ig) gene segments (V(H), D, J(H)) used to encode the variable region of the heavy chain of an anti-DNA autoantibody were sequenced. All three gene segments could be identified as members of established Ig gene segment families. In fact, the heavy chain of an antibody directed against the hapten L-glutamine₆₀-L-alanine₃₀-L-tyrosine₁₀ polymer (GAT) was found to utilize the same combination of V(H), D, and J(H) gene segments as the anti-DNA autoantibody. These results clearly indicate that autoantibodies are encoded by gene segments from the same Ig gene families used to encode antibodies to exogenous antigens. However, the discovery that this anti-DNA autoantibody is encoded by the same V(H) gene segment which encodes another anti-DNA autoantibody, derived from a different autoimmune mouse strain, supports the idea that certain V(H) gene segments may, in fact, be preferentially used to encode autoantibodies.

No description available.