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Cheng, Duo

University of British Columbia

Glia are dynamic modulators required for the development and function of the nervous system, and various cell surface receptors which interpret the extracellular landscape are integral to their actions. However, the mechanisms by which glia accomplish such tasks remain to be fully characterized. This thesis explores the function of a major transmembrane heparan sulfate proteoglycan (HSPG) protein, Syndecan (Sdc), and its function in the Drosophila nervous system. In the central nervous system, where Syndecan is robustly expressed, I have shown that its downregulation in glia leads to a reduction in neuroblasts population, resulting in shrinkage of the brain lobe. In parallel, I observed elongation of the ventral nerve cord, indicative of disruption to the glial-ECM interactions. Syndecan is also found in high levels in various glial membranes within the peripheral nervous system, where I observed distinctive and cell-autonomous defects upon downregulation of Syndecan expression within each glial layer. Our results suggest Syndecan is required for the maintenance of blood-nerve barrier integrity, as Syndecan knockdown disrupted separate junction morphology of peripheral subperineurial glia. Moreover, I showed Syndecan is required for the ensheathment by multiple glial populations, including perineurial and wrapping glia. In particular, laminin deposition in the basal lamina surrounding the peripheral nerve was reduced upon knockdown of Syndecan in the outermost (perineurial) glial layer. Overall, these results demonstrate several novel aspects of Syndecan’s role in vivo during neural and glial development.

Text

2021-06-03

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/78525

Cell and Developmental Biology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/