Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709621
Title: Validation of nWASP as a therapeutic target in chronic and non-healing human wounds
Author: Frugtniet, Bethan
ISNI:       0000 0004 6059 3039
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2017
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Abstract:
Introduction: Chronic wounds do not progress through the normal wound healing process and represent a significant burden to healthcare systems and to the hundreds of thousands of patients in the UK who suffer with them. There are significant challenges in both understanding the underlying biology and developing novel therapies to encourage healing of chronic wounds. nWASP is a regulator of the actin cytoskeleton through interactions with the Arp2/3 complex and is involved in a variety of roles particularly at the cell membrane in protrusion and vesicle formation. This study investigates the expression pattern of nWASP in chronic wound tissues and explores, through both in vitro and in vivo models, the cellular and molecular impact of nWASP activity on the function of cells involved in wound healing and also in cancer cells. Methods: Clinical cohorts from patients with chronic wounds and lung cancer were tested for the expression of nWASP expression through qPCR analysis. Cell models, based on keratinocytes (HaCaT) and vascular endothelial (HECV) cells were employed to evaluate the influence of nWASP on cellular functions that are key to the healing process genetic knockdown and/or using nWASP-specific inhibitors. Resulting cellular signalling changes was explored by way of protein kinase arrays and Western blotting and in vivo models were used to assess the therapeutic values of topical application of nWASP inhibitors in wound healing. A similar approach was employed using lung cancer cell models. Results: nWASP was found to be significantly elevated at the transcript level in human non-healing chronic wound tissues compared with healing tissues. nWASP inhibitors, namely wiskostatin and 187-1, and knockdown, altered the spreading and attachment behaviour of HaCaT cells. Several protein signalling pathways affected by nWASP inhibition were identified, in particular TrkB signalling and downstream PLCγ1 phosphorylation were shown to be impaired by nWASP inhibition in HaCaT cells. Healing of hole-punch wounds in the ears of db/db mice, a diabetic model which exhibit impaired wound healing, was improved by topical and systemic nWASP inhibitor treatment. In the context of lung cancer, nWASP expression was significantly correlated with the survival of the patients. Invasive behaviour was found to be impaired in the more invasive SK MES-1 cell line with motility and migration being affected in A-549 cells following nWASP inhibitor treatment. Decreased paxillin activity in membrane focal adhesions was shown following nWASP inhibition and knockdown. Conclusions: This study suggests that nWASP activity may be related to the nonhealing behaviour of chronic wounds and that its activity can affect function of keratinocytes and endothelial cells. Together with the findings in the in vivo models, it strongly points nWASP as a therapeutic target in non-healing wounds. nWASP is also a potential biomarker and therapeutic target in human lung cancer, in which it influences the aggressive behaviour of lung cancer cells. The study has identified that TrkB, PLCγ1 and paxillin signalling can be controlled by nWASP activity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.709621  DOI: Not available
Keywords: R Medicine (General)
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