Influence of vitamin D on metabolism of immunomodulatory lipid mediators in tuberculosis (360G-Wellcome-202101_Z_16_Z)

Background: Understanding the mechanisms whereby vitamin D may enhance resolution of inflammation post-tuberculosis might lead to new host-directed therapies for this disease. My supervisor has previously shown that the active vitamin D metabolite 1,25(OH)2D induces the 5-lipoxygenase enzyme which is key to the production of a novel genus of host protective mediators termed ‘specialized pro-resolving mediators’ from essential fatty acids. These mediators include the lipoxins from arachidonic acid and the resolvins, protectins and maresins from docosahexaenoic acid. The effects of M. tuberculosis and vitamin D on the metabolism of these mediators have yet to be characterised. Key Goals: To determine the influence of in vitro co-culture with 1,25(OH)2D and its precursor 25-hydroxyvitamin D (25[OH]D) on: 1. Concentrations of pro-resolving mediators in supernatants aspirated from M. tuberculosis-stimulated monocyte-derived macrophages (MDM) 2. Expression of key enzymes implicated in the synthesis and catabolism of pro-resolving mediators in M. tuberculosis-stimulated MDM. Methods MDM co-cultured with vitamin D metabolites vs. vehicle control will be infected with M. tuberculosis: supernatants and RNA will be harvested at 96 hr post-infection. Concentrations of lipid mediators will be determined by LC MS-MS at the QMUL Lipid Mediator Unit, and gene expression will be assayed by RT-PCR.