Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

Browse

Filters

2006 - 200912020 - 20211

Settings

Subject: search.filters.subject.eNOS

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Investigation of the molecular mechanisms of vascular endothelial dysfunction in Hutchinson-Gilford progeria syndrome through in vitro 2D and 3D models
    (2021) Gete, Yantenew; Cao, Kan; Cell Biology & Molecular Genetics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder with features of accelerated aging. Predominantly, HGPS is caused by a de novo point mutation in the LMNA gene (c.1824C > T; p.G608G) resulting in progerin, a toxic lamin A protein variant. Children with HGPS typically die from coronary artery diseases or strokes at an average age of 14.6 years. Endothelial dysfunction is a known driver of cardiovascular pathogenesis; however, it is currently unknown how progerin antagonizes endothelial function in HGPS. In this study, I used human iPSC-derived endothelial cell (iPSC-EC) models that cultured under both static and fluidic culture conditions. HGPS iPSC-ECs show reduced endothelial nitric oxide synthase (eNOS) expression and activity compared to healthy controls and concomitant decreases in intracellular nitric oxide (NO) level, which result in deficits in capillary-like microvascular network formation. In addition, expression of matrix metalloproteinase 9 (MMP-9) was reduced in HGPS iPSC-ECs while expression of tissue inhibitor metalloproteinases 1 and 2 (TIMP1 and TIMP2) were upregulated relative to healthy controls. Moreover, I used an adenine base editor (ABE7.10max-VRQR) to correct the pathogenic c.1824C > T allele in HGPS iPSC-ECs. Remarkably, ABE7.10max-VRQR correction of the HGPS mutation significantly reduced progerin expression to a basal level, rescued nuclear blebbing, increased intracellular NO level, normalized TIMPs , and restored angiogenic competence in HGPS iPSC-ECs. Furthermore, to elucidate the effects of progerin on endothelial cells and vascular remodeling, in collaboration with Dr. Truskey’s lab at Duke university, we developed tissue-engineered blood vessels (TEBVs) using iPSC-ECs and smooth muscle cells (iPSC-SMCs) from normal and HGPS patients. Relative to normal TEBVs, HGPS TEBVs showed reduced function and exhibited markers of cardiovascular disease associated with endothelium, including a reduction in both vasoconstriction and vasodilation with increased inflammation markers, VCAM-1 and E-selectin protein. Hence, the TEBV model has identified a role of the endothelium in HGPS. Together, the results of the study provide molecular insights of endothelial dysfunction in HGPS and suggest that ABE7.10max-VRQR could be a promising therapeutic approach for correcting HGPS-related cardiovascular phenotypes.
  • Thumbnail Image
    Item
    NFKB1 Gene Promoter Polymorphism and Unidirectional Laminar Shear Stress: Implications for NF-kB Activation, eNOS Protein Expression and Endothelial Function
    (2006-06-04) Park, Joon Young; Brown, Michael D.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Exercise stimulus can be defined as endothelial wall shear stress. In the endothelial cells, the nuclear factor-kappa B (NF-κB) is an important intracellular signaling molecule by which changes in wall shear stress, sensed by mechanosensors, are transduced into the nucleus to initiate downstream eNOS gene expression. Recently, a polymorphism in the promoter region of the gene encoding a p50/p105 NF-κB subunit, NFKB1, has been identified. The NFKB1 ATTG insertion (I) / deletion (D) (NFKB1 I/D) promoter polymorphism transcriptionally regulates NFKB1 gene expression. However, the functional significance of this polymorphism has not been elucidated in endothelial cells under LSS and in endothelial function in humans. Therefore, the purpose of this study was to investigate whether the NFKB1 I/D promoter polymorphism had functional genetic properties in human umbilical vein endothelial cells (HUVECs) under physiological levels of unidirectional laminar shear stress (LSS), and further, whether the polymorphism was associated with changes in endothelial function after endurance exercise training in pre- and stage I hypertensive individuals. The major findings of the present study were that 1) a protein present in HUVECs preferentially and specifically binds to the I allele promoter compare to the D allele; 2) the I allele had significantly higher promoter activity than the D allele; and accordingly, the II homozygote cells had higher p50/p105 NFKB1 protein levels than the DD homozygote cells; 3) the II homozygote cells showed a greater increase in eNOS protein levels than the DD homozygote cells under unidirectional LSS; and 4) the I-allele carrier group had a greater reactive hyperemic forearm blood flow response, a measure of endothelial function, before exercise training; however, the NFKB1 I/D polymorphism was not significantly associated with the differential changes in endothelial function following exercise training. These results have potential clinical implications for endothelial dysfunction that are related to the development and progression of atherosclerosis and cardiovascular disease. In addition, our findings provide insight into the molecular mechanisms involved in the intracellular signaling transduction process of eNOS gene expression and function of the NFKB1 gene promoter region.