Medicine and Health Sciences Commons^™

The Role Of Dlc1Β In Attenuating Cardiac Ischemia-Reperfusion Injury During Heart Transplantation, Samantha L. Collings

Electronic Thesis and Dissertation Repository

Cardiac ischemia-reperfusion injury (IRI) occurs intra-operatively during heart transplantation (HTx), underpinning graft survival. Past research implicated the PI3K/Akt1 & RhoA/ROCK pathways in IRI. Rho-GTPase activity/Akt regulates Deleted-in-liver-cancer 1 protein’s beta-isoform (DLC1β). Therefore, we hypothesized that DLC1β overexpression (OE) had anti-apoptotic effects. In vitro, HL-1 cells (mouse cardiomyocytes) received chamber hypoxia-oxygenation reperfusion (H/R) for 24H4R with/without DLC1β plasmid, before collection for protein/mRNA analyses. DLC1β-OE resulted in downregulated pro-apoptotic mRNA expression (Bax/Cycs/Casp3), upregulated protective mRNA targets (BCl2/Akt1) and less late/early apoptosis via flow cytometry. Results were confirmed via H9C2 (rat cardiomyocyte) cell lines. In vivo, C57/BL6 mice received heterotopic HTx with/without DLC1β-OE …

Characterization Of Wilms' Tumour 1 (Wt1) As A Biomarker For Fibrosis In Duchenne Muscular Dystrophy, Patrick Murphy

Electronic Thesis and Dissertation Repository

Duchenne muscular dystrophy (DMD) is the most common inherited pediatric muscle dystrophy. It is characterized by muscle degeneration, resulting in fibrosis that is a significant impediment to both endogenous muscle repair and any potential regenerative strategy. At present, there are few therapies that specifically address fibrosis and microenvironment improvement, but one possibility rests in targeting the Wilms’ tumour 1 (Wt1) protein. Wt1 is a zinc finger transcription factor, recently shown to be expressed in fibrotic conditions such as Dupuytren’s disease and pulmonary fibrosis. This thesis examines the expression pattern of Wt1 in several mouse models of DMD, through both histological …

Modulation Of Inflammation Driven Wound Healing After Glaucoma Surgery, James J. Armstrong

Electronic Thesis and Dissertation Repository

Dysregulated wound healing contributes to most currently unanswered ophthalmological morbidity. Opacification and structure altering contractures compromise the delicate ocular anatomy upon which ocular function and healthy vision are reliant. Glaucoma filtration surgery, corneal stromal injury, proliferative vitreoretinopathy and age-related macular degeneration are major contributors to ocular morbidity – all with myofibroblast transdifferentiation and pathognomonic scarring activity at their core.

This thesis aims to revaluate the means by which dysregulated ocular wound healing is combated with evidence describing a novel strategy to mitigate its effects. A translational approach was used. An initial retrospective analysis of over ten thousand glaucoma surgeries found …

Yap-Mediated Mechanotransduction Promotes Fibrotic Activity, Michael Racanelli

Electronic Thesis and Dissertation Repository

Fibrosis, a phenotype associated with mortality for a multitude of diseases, has no disease-modifying treatment. We examine if Verteporfin (VP), an inhibitor of the YAP-TEAD complex, currently in wide clinical use for macular degeneration, can inhibit pro-fibrotic gene expression in human dermal fibroblasts. Also, an in vivo approach was taken using a Pten-deficient mouse of progressive skin fibrosis for examining effects on melanoma metastasis. We found that treatment with VP reduced basal expression of a variety of profibrotic genes and prevented a myofibroblast-like phenotype in response to TGFβ1. Indeed, genome-wide expression analysis suggested that VP inhibited a cluster of …

The Effect Of Function-Blocking Rhamm Peptides In A Mouse Model Of Bleomycin-Induced Systemic Sclerosis, Kitty Y. Wu

Electronic Thesis and Dissertation Repository

Systemic sclerosis is a chronic, fibrotic disorder associated with high disease-specific mortality and morbidity. Cutaneous manifestations include dermal thickening and obliteration of dermal adipose tissue. The efficacy of function-blocking Rhamm peptides, NPI-110 and NPI-106, were tested in reducing skin fibrosis and promoting adipogenesis in a bleomycin-induced mouse model of systemic sclerosis. NPI-110 reduced both visible measures of fibrosis (dermal thickness, collagen density, and fibril bundling) and mRNA expression of pro-fibrotic genes (Tgfb1, c-Myc, Col1a1, Col3a1). While there was no measurable change in dermal adipose thickness, NPI-110 treatment upregulated Perilipin mRNA and Adiponectin protein expression and is therefore hypothesized to …

Regulation Of Phosphatase And Tensin Homolog Expression And Activity By Transforming Growth-Factor Beta In The Trabecular Meshwork Cells: Implications For Primary Open Angle Glaucoma, Nikoleta Tellios

Electronic Thesis and Dissertation Repository

Glaucoma is a multifactorial condition caused, in part, by fibrosis of the sieve-like trabecular meshwork (TM) tissue, which impedes drainage of aqueous humor (AH), leading to increased intraocular pressure and associated optic nerve damage and blindness. Fibrosis of the TM is mainly caused by the increased levels of active transforming growth factor-β 2 (TGFβ2) in the AH of glaucoma patients.

Previous reports have shown that TGFβ decreases the expression of Phosphatase and Tensin Homolog (PTEN) gene and that PTEN is a major regulator of ECM deposition. In this study we investigate the regulation of PTEN protein expression and …

Angiogenic Therapy In A Fibrotic Murine Model Of Duchenne Muscular Dystrophy, Kelly M. Gutpell

Electronic Thesis and Dissertation Repository

Duchenne muscular dystrophy (DMD) is a devastating neuromuscular disorder that affects approximately 1 in 5000 males. Vascular-targeted therapy has been proposed as a treatment for DMD to reduce ischemia and enhance endogenous repair. Additionally, a more vascularized environment may enhance regenerative approaches currently under investigation. Vascular endothelial growth factor (VEGF) and angiopoietin-1 (ANG1) are two of the most studied pro-angiogenic factors for this approach. To date, little is known regarding the effect of these pro-angiogenic factors on muscle function and whether they may exacerbate fibrosis in a relevant murine model of DMD. The first aim of this thesis was to …

Non-Invasive Determination Of Pre-Clinical Markers Of Cardiovascular Diseases In Low Birth Weight And Maternal Western Diet Guinea Pig Offspring Exposed To A Postnatal Western Diet, Jacky Chiu

Electronic Thesis and Dissertation Repository

Low birth weight (LBW), and maternal Western Diet (WD) consumption have both been independently implicated to increase the risk of developing cardiovascular diseases (CVDs) in later life. These fetal programmed risks are also believed to exacerbate the effects of a postnatal WD pattern. Therefore, resulting in the development of pre-clinical markers of CVDs, such as insulin resistance (IR), coronary circulation disruptions. This thesis aimed to elucidate the roles of sub-optimal in utero growth through placental insufficiency, or chronic maternal WD consumption, and postnatal WD consumption on the long-term programming of CVDs in a guinea pig model. Early pre-clinical markers of …

Tak1 Mediates Tgf Beta-1 Responses In Gingival Fibroblasts, Hanna Kuk

Electronic Thesis and Dissertation Repository

In fibroblasts, transforming growth factor β-1 (TGFβ1) signals via canonical and non-canonical pathways to promote wound healing or hyper-contractile responses resulting in scars. The oral cavity however does not scar and fibrotic responses such as gingival hyperplasia are characterized by a hyper-proliferative response. The involvement of non-canonical, TGFβ-activated kinase-1 (TAK1) - mediated TGFβ1 signaling in gingival fibroblasts has not been previously examined. Here I show that TAK1 selective inhibitor (5Z)-7-Oxozeaenol blocks TGFβ1-induced expression of wound healing and fibrotic marker CCN2 (connective tissue growth factor) in gingival fibroblasts. Genome-wide expression profiling revealed that essentially all TGFβ1 induced genes were in fact …

Evaluation Of Matricellular Proteins As Potential Therapeutics For The Treatment Of Human Chronic Skin Wounds, Christopher G. Elliott

Electronic Thesis and Dissertation Repository

There is currently an unmet need for treatments to enhance healing of human chronic skin wounds. Previously, therapy development has focused on growth factors and physical matrices, often resulting in disappointing clinical outcomes. In this thesis, we approached chronic skin wound treatment with a focus on fibrosis and matricellular proteins. Fibrosis is a pathological condition where tissue repair continues, unchecked, resulting in excess contraction, matrix accumulation and fibrogenic growth factor activity; features critically reduced in chronic skin wounds. Identifying factors that promote fibrosis may offer new therapeutic targets for use in chronic skin wounds. Two such factors are the matricellular …