Institute of Biomedical Studies

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Browsing Institute of Biomedical Studies by Author "Connolly, John Edward."

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    Investigating the role of novel gene -C20orf197.
    (2016-04-05) Wang, Jingjing, 1984-; Connolly, John Edward.
    The C20orf197 gene which is on chromosome 20 open reading frame 197, was sequenced at least 15 years ago, but even today, it still remains uncharacterised for the public. Meanwhile, over the last few decades it has become apparent that the incidence of acute promyelocytic leukaemia (APL) is increasing. APL is characterised by the accumulation of immature granulocytes, due to these cells being unexpectedly terminated at an early naive differentiation stage. C20orf197 is a novel discovery gene and we have found it has a great effect on granulocyte differentiation. Therefore C20orf197 is a good candidate for a potential novel therapeutic intervention in the treatment of myeloid leukaemia. The NB4 cell line has been used as a model for studies of APL and granulocyte differentiation in vitro. Though the mechanisms underlying APL/granulocyte differentiation have been studied for about three decades, a comprehensive picture of the molecular nature remains incomplete. After several hypotheses have been disproved as shown in supplementary chapter, in this dissertation, based on our own studies, we, in the world wide, for the first time elucidate the function of this novel C20orf197 gene and propose that this gene has an effect on granulocyte differentiation. We first collected and combined all the clues from human tissue, cell lines expression and structure prediction, then we established knockout C20orf197 NB4 cell lines and set up baseline transcriptional profiles of ATRA induced wild type NB4. Then we examined global transcriptional change in the NB4 knockout C20orf197 cell line before and after induction by ATRA. After validation of the transcriptional landscape by cytokines and expression of differentiation markers at single time point and different time points, we found C20orf197 was the contributor for granulocyte differentiation. Thus, our studies provide first-hand information in the world, about the biological role of the uncharacterised novel gene C20orf197 and C20orf197 dependent or independent processes.
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    Respiratory Syncytial Virus triggers immune tolerance through induction of tolerogenic dendritic cells and expansion of regulatory T cells.
    (2010-06-23T12:28:05Z) Guo, Haisu.; Connolly, John Edward.; Biomedical Studies.; Baylor University. Institute of Biomedical Studies.
    Dendritic cells have the ability to control the balance between immunity and tolerance. Upon viral exposure, Dendritic Cells (DCs) steadily detect pathogens and exert their antigen presentation function to induce adaptive T cell response. Respiratory Syncytial Virus (RSV) is an important respiratory pathogen in infants and young children worldwide. Here we show that RSV exposure polarizes DC maturation to a tolerogenic state. RSV exposed DCs (RSV-DCs) are unable to prime allogeneic CD4+ T cell proliferation and cytokine production. Strikingly, RSV exposed DCs are able to efficiently inhibit on-going Mixed Leukocyte Reaction (MLR) in trans. Phenotypic characterization of RSV-DCs indicates that they express a variety of surface inhibitory molecules and secrete high amount of the cytokine IL-10. Autocrine IL-10 receptor signaling is required for tolerogenic conversion. A direct comparison with pharmacologically generated tolerogenic DCs indicates RSV-DCs are much more potent at inhibiting CD4+ T cell alloproliferation. Furthermore, we find that RSV-DCs propagate their tolerogenic signal through expansion of regulatory T cells (Tregs). RSV- DCs induce the selective expansion of CD4+/CD25+/FoxP3+/CTLA+/GITR+ Tregs in the bulk T cell population. These Tregs are able to inhibit on-going MLR in trans, indicating their functional potency. An analysis of the non-proliferating target CD4+ T cells indicates that they are in a state of phenotypic and functional anergy. These T cells express anergy markers and are unresponsive to secondary anti-CD3/CD28 restimulation. Interaction of B7 negative co-stimualtor PD-L1 and its receptor PD-1 are required for Treg expansion and function as blockade led to a reversal of anergy induction in the target population. These in vitro observations led us to investigate the impact of RSV-DCs on immune tolerance in vivo. We did preliminary studies demonstrating RSV exposure induces BALB/c bone marrow derived DCs (BM-DCs) tolerogenic characterized by inhibition of C57BL/6 CD4 T cell alloproliferation and upregulation of mouse PD-L1 molecule. Similarly to what we observed in human cells, RSV-mouse DCs are able to expand a population of CD4+CD25+FoxP3+ regulatory T cells. These cells with immune suppressive function can then be adoptively transferred into murine models of autoimmune diseases and organ transplantion to suppress antigen-specific immune activation in vivo.