Davies started her scientific career at the University of Wales, where she graduated with a degree in biochemistry in 1975 before starting a PhD in microbialbiochemistry.[4] In 1979 she completed her graduate research, investigated the biochemistry of the most abundant enzyme on earth: ribulose-1-5-bisphosphate carboxylase (RuBisCO).[4]
Davies identified that in patients with asthma, the bronchial epithelial barrier is structurally and functionally compromised. This defective barrier may permit the passage of allergens into the tissue of the respiratory tract, which can activate the immune system and trigger the allergic inflammation in asthma patient's lungs.[6] As a result, targeting this defective barrier may offer opportunity to help patients with difficult to treat asthma.
She has proposed that the reason common cold (rhinovirus) viruses can exacerbate asthma is because of a lesion in the immune response of epithelial cells in patients with asthma.[4] As part of this work, she developed tissue engineered in vitro models of the human airway that allowed investigations without the use of animals.[7] The models make use of human airway epithelial and dendritic cells from patients with and without asthma.[7] She showed that the bronchial epithelial cells of asthmatic individuals have a deficient anti-viral response to rhinovirus infections;[8] but suggested this can be corrected through the introduction of interferon-beta, an anti-viral protein.[4] In 2003 Davies, Stephen Holgate and Ratko Djukanovic [Wikidata] founded the University spin-off company Synairgen.[9][10] Synairgen produce an inhaled interferon-beta drug (SNG001) that can treat patients with asthma and COPD that has been worsened by viruses.[4]
Her research demonstrated that the epithelial mesenchymal trophic unit is activated in patients with chronic asthma,[11] which contributes to the progression and severity of asthma because of aberrant repair response.[4] Davies was appointed head of clinical and experimental sciences in the faculty of medicine in 2011.[4]
During the COVID-19 pandemic it emerged that Synairgen's SNG001 was a potential treatment for COVID-19.[12] In a clinical trial of one hundred hospitalised COVID-19 patients, patients treated with SNG001 were 80% less likely to develop a serious form of COVID-19.[13] After news of the successful drug trail, share prices in Synairgen rose 540%.[13]
^Holgate, Stephen T.; Holloway, John; Wilson, Susan; Bucchieri, Fabio; Puddicombe, Sarah; Davies, Donna E. (2004). "Epithelial–Mesenchymal Communication in the Pathogenesis of Chronic Asthma". Proceedings of the American Thoracic Society. 1 (2): 93–98. doi:10.1513/pats.2306034. hdl:10447/23765. ISSN1546-3222. PMID16113419.