Validation of AMP activated protein kinase (AMPK) as a therapeutic target in lung inflammation

  • Yan Hui Giam

    Student thesis: Doctoral ThesisDoctor of Philosophy

    Abstract

    Bronchiectasis is a chronic respiratory disease characterised by permanent bronchial dilation and a clinical syndrome of cough and sputum production. Most bronchiectasis patients experience chronic bacterial infections and neutrophilic inflammation. Neutrophil dysfunction in bronchiectasis allows prolonged bacterial infections. Hence, there is a need to develop new anti-inflammatory treatments to target neutrophilic inflammation. Most clinical trials of anti-inflammatory targets have been unsuccessful. AMPK is an energy sensor kinase, and its activity has been shown to modulate neutrophil functions. Thus, this thesis aims to validate AMPK as a novel therapeutic target for bronchiectasis. As AMPK is also involved in regulating cell metabolism, metabolic reprogramming of neutrophils was also studied to understand how immunometabolism can influence neutrophil function.

    Additionally, COVID-19 was also studied in this thesis, as an acute inflammatory respiratory disease also associated with neutrophil dysfunction. Increased neutrophil recruitment in the lung was described in previous studies, with increased neutrophil extracellular traps (NETs) release associated with increased disease severity. The drug SFX-01, is a stabilised formulation of sulforaphane, and was tested in a randomized controlled trial as a preventive drug for onset of ARDS in COVID-19 and pneumonia patients. As sulforaphane has been shown to activate AMPK, and induce NRF2 accumulation, this study aims to characterise the effects of SFX-01 on these 2 proteins, and understand changes in inflammation of COVID-19 pneumonia patients.

    This thesis presents data from a large European observational cohort study of bronchiectasis patients called BRIDGE which is divided into a pilot study and a main study. Airway lactate and glucose was characterised in the BRIDGE pilot study, and analysed with various clinical and inflammatory data. Whole blood was then collected from age-matched controls and bronchiectasis patients, to isolate neutrophils and conduct neutrophil functional assays with selected AMPK modulators.

    Exploratory data from the STAR-COVID-19 trial was then presented. Comparisons of the activated form of AMPK (phospho-AMPK) and marker for NRF2 (NQO1) were made between SFX-01 and placebo, and also between COVID-19 and pneumonia patients, on both day 1 and 15 following treatment. The inflammatory profiles of serum from our cohort was also analysed on day 1 and longitudinally. Functional assays was then included and compared between treatment arms and disease groups to determine if an NRF2 activator could alter AMPK activation and improve neutrophil function in COVID-19 pneumonia patients.

    Finally, this thesis presents metabolomics data of peripheral neutrophils collected from a cohort of 80 bronchiectasis patients, 80 COVID-19 patients, and 62 age-matched controls. Selected metabolic pathways were included in targeted analysis, and untargeted analysis was also conducted to look at the neutrophil metabolome in a hypothesis-free approach. Neutrophils treated with selected inflammatory stimuli was also included in the metabolomics analysis, to understand how each inflammatory stimuli induces metabolic reprogramming in neutrophils.
    Date of Award2023
    Original languageEnglish
    SponsorsChief Scientist Office
    SupervisorJames Chalmers (Supervisor) & Amelia Shoemark (Supervisor)

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