The Investigations of the Effect of In-Vitro Combination Treatment: Curcumin, Aspirin, and Sulforaphane on Idiopathic Pulmonary Fibrosis
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Bui, Sarah
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Abstract
Idiopathic Pulmonary Fibrosis (IPF) is a fatal interstitial lung disease characterized by an abundance of activated fibroblasts, which deposits excessive scar tissue in the lung. IPF is believed to be a result of an aberrant wound healing process in which fibroblasts are activated, undergo proliferation, and promote the excessive deposition of extracellular matrix. The source of injury to the alveolar epithelia which triggers this repair is unknown, however as a result of this aberrant process the fibroblasts appear to assume an apoptotic resistant phenotype. Curcumin has been shown to have global anti-fibrotic and apoptotic properties; however its bioavailability limits its application as a therapeutic. We sought to enhance curcumin’s anti-fibrotic properties via its combination with aspirin and sulforaphane (CAS) in IPF and normal derived primary human fibroblasts in vitro. In addition, we sought to reveal the mechanism of apoptosis induced by this combined therapy. CAS enhanced anti-fibrotic properties were demonstrated through the inhibition of fibroblast activation markers collagen A1 and smooth muscle actin. CAS exposure resulted in a significant increase in cell death, 73.97±31.31% (p=0.0474*) and 49.64 ±6.87% (p=0.0021*) decrease in normal fibroblast (N-F) and IPF fibroblast (IPF-F) over 48 hours. CAS-induced cell death was Caspase 3/7 dependent and results in subsequent proteolytic cleavage of PARP. Previous studies have associated sulforaphane mediated apoptosis with the ERK-MEK pathway and curcumin via the NFκβ pathway. Comparison of N-F and IPF-F mediate CAS cell death demonstrated a differential duration of ERK activation, sustained verses transient, which may be associated with N-F susceptibility to CAS and the apparent apoptotic resistance in IPF-F. NFκβ pathway proteins such as BclXL, AKT, beta catenin were also differentially regulated between IPF-F and N-F. The CAS combinatorial challenge demonstrated an effective apoptotic response in the cell lines. The contrasting routes of apoptosis between IPF-F and its N-F seen here highlight a significance difference between these cells which may indicate a significant role in disease progression. A further understanding of the apoptotic mechanisms in IPF-F will identify cell specific targets for the directed elimination of IPF-F while preserving the integrity of N-F and epithelial populations in the IPF lung.
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This thesis has been embargoed for 1 year. It will not be available until April 2018 at the earliest.
Keywords
Idiopathic pulmonary fibrosis, Apoptosis, Fibroblasts, Curcumin