Date of Graduation

Spring 2022

Degree

Master of Natural and Applied Science in Biology

Department

Biology

Committee Chair

Kyoungtae Kim

Abstract

Blood vessel maturation is characterized by the recruitment and attachment of vascular smooth muscle cells (vSMCs) around immature blood vessels, which ultimately form the tunica media. Improper maturation can lead to vascular birth defects ranging from minor birthmarks to lethal brain aneurysms. Previously, our lab demonstrated that hemodynamic force plays an important role to regulate vSMCs recruitment from neighboring low-flow to high-flow vessels followed by the attachment of these vSMCs to the high-flow vessels. To understand the reason for the preferred attachment of vSMCs to high-flow vessels, instead of low-flow vessels, I hypothesize that hemodynamic force modulates the expression of extracellular matrix genes to promote the deposition of a thick basement membrane around the immature high-flow vessels to increase its adhesiveness to migrating vSMCs. To test this hypothesis, I utilized an extraembryonic tissue called the yolk sac, which is a thin/transparent membrane only comprised of simple blood vessels, and I compared gene expression differences by qPCR between yolk sac tissues under normal blood flow with those having reduced blood flow. I found that there is a decrease in matrix metalloproteinase-9 (MMP-9) expression in high-flow vessels as compared to low-flow vessels. My data support our hypothesis as lowering MMP9 should promote deposition of a thicker basement membrane, thus enhancing the attachment of vSMCs to high-flow vessels.

Keywords

vascular smooth muscle cells, vessel maturation, hemodynamic force, extracellular matrix genes, basement membrane

Subject Categories

Developmental Biology

Copyright

© Israt Jahan

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