akarsan@bccrc.ca

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Research Interests:

My lab focuses on two major areas: (1) Understanding the molecular basis of the preleukemic bone marrow failure conditions called myelodysplastic syndromes (MDS); and (2) Determining the role of the endothelium in the development of the hematopoietic system. With respect to both areas we have been studying the role of two pathways: innate immune signaling as represented by the Toll-like receptor (TLR) pathways, and the Notch signaling pathway.

We have recently demonstrated that microRNAs that reside on the long arm of chromosome 5 act to regulate innate immune signaling. Deletion of chromosome arm 5q is the commonest structural anomaly seen in MDS, and our current work is centred around establishing the function of these microRNAs and deregulated innate immune signaling in the manifestations of MDS. We are using a variety of in vivo transplantation assays, in vitro cell biology and cell signaling studies as well as genomic approaches to answer these questions.

In other work related to innate immune signaling, we have identified a novel protein by differential proteomic analysis that appears to act as a scaffold protein in a MyD88-independent TLR signal transduction pathway. Expression analyses indicate that this molecule is highly expressed in the microvasculature. Molecular and cellular studies to elucidate the mechanisms of action of this protein are ongoing. As well we have generated a gene-targeted mouse model that demonstrates that loss of this protein is incompatible with life past mid-gestation. Currently, we are generating a conditional gene-targeted mouse model to gain a better understanding of the physiologic role of this protein.

My lab has also had a long-standing interest in the role of Notch signaling in the endothelium. We have generated a conditional, inducible mouse model in which we are able to regulate Notch signaling. Using this and other models we are studying how endothelial cells contribute to hematopoietic development both at the initial stages of intraembryonic hematopoiesis where hematopoietic stem cells are thought to derive from the endothelium, as well as during fetal liver and adult hematopoiesis, where the endothelium may act as a niche to regulate stem cell self renewal and/or differentiation.

See Also:

• Aly Karsan's Lab