This project aims to develop a novel Dictyostelium model to investigate the potential for bitter tastants as new treatments for asthma, and replace the mammalian models currently used for these studies.
Bitter tasting compounds have been demonstrated to open the airways in the lung, suggesting a role for these compounds in the treatment of asthma. Research into bitter compounds and the way they work in asthma has focused on using lung tissue obtained from guinea pigs and mice, but also from humans. This research involves using ex vivo tissue to elucidate the mechanism by which bitter compounds trigger muscle relaxation (related to relieving asthma induction), and uses large numbers of animals.
Developing alternative non-animal systems to investigate the mechanisms of bitter tasting compounds will reduce the use of animals in this research area, and provide experimental approaches unavailable in animal models. This project proposes to develop a two stage system, initially using the social amoeba Dictyostelium to identify the mechanism of action of bitter tastants as bronchodilators, and subsequently using human cells to confirm discoveries are relevant to asthma treatment.
Research details and methods
A variety of 'reference' bitter tastants associated with bronchodilation will be screened using Dictyostelium growth as a model. Sensitivity of Dictyostelium to these compounds will enable a genetic screen to identify novel gene products controlling sensitivity to bitter compounds. A mutant library used in the screen will be used to isolate new bitter tastant targets. Recapitulation of identified mutants in wild-type cell lines will confirm a role for each target in sensitivity. These mutants will also be rescued by expression of the endogenous gene and by expression of the human homologue. Resistance will be monitored using sensitivity to growth inhibition, movement, and development. This approach will enable the analysis of these new targets without using animals.
Bitter compounds and identified signalling pathways from the Dictyostelium studies will be investigated in human-derived tissues to illustrate functional mechanism(s) for these compounds in human tissues.
Williams RSB and Andrews PLR (2019). Advice on avoiding the Valley of Death: Insights from a 3Rs model of aversive and emetic compound identification. ALTEX 36(3):466-469. doi: 10.14573/altex.1810182
Cocorocchio M et al. (2018). Curcumin and derivatives function through protein phosphatase 2A and presenilin orthologues in Dictyostelium discoideum. Disease Models and Mechanisms 11(1). doi: 10.1242/dmm.032375
Frej AD et al. (2017). Tipping the scales: Lessons from simple model systems on inositol imbalance in neurological disorders. European journal of cell biology 96(2):154-163. doi: 10.1016/j.ejcb.2017.01.007
Vauzour D et al. (2017). Nutrition for the ageing brain: Towards evidence for an optimal diet. Ageing research reviews 35:222-240. doi: 10.1016/j.arr.2016.09.010
Frej AD et al. (2016). The Inositol-3-Phosphate Synthase Biosynthetic Enzyme Has Distinct Catalytic and Metabolic Roles. Molecular and Cellular Biology 36:1464 –1479. doi: 10.1128/MCB.00039-16
Otto GP et al. (2016). Non-Catalytic Roles of Presenilin Throughout Evolution. Journal of Alzheimer's disease 52(4):1177-87. doi: 10.3233/JAD-150940
Otto GP et al. (2016). Employing Dictyostelium as an Advantageous 3Rs Model for Pharmacogenetic Research. Methods in molecular biology (Clifton, N.J.) 1407:123-30. doi: 10.1007/978-1-4939-3480-5_9
Pistollato F et al. (2016). Alzheimer disease research in the 21st century: past and current failures, new perspectives and funding priorities. Oncotarget 7(26):38999-39016. doi: 10.18632/oncotarget.9175
- Further Funding: NC3Rs PhD Studentship, Find the target of valproic acid: pioneering the use of a non-animal model for basic biomedical (epilepsy) research, September 2014, £90,000
- Further Funding: NC3Rs Project Grant, Replacing, refining and reducing animal usage in epilepsy research using a non-sentient model, January 2010, £415,373