Inappropriate immune responses, including the accumulation and activation of leukocytes, is a shared pathological feature seen in advancing age and immune-mediated inflammatory diseases (IMIDs). Cellular accumulation is therefore an attractive target for therapeutic intervention. However, attempts to target these processes by modulating leukocyte recruitment and retention, with e.g., chemokine receptor inhibitors, have not been successful to date. We have identified a series of immunopeptides that regulate leukocyte trafficking and offer potential therapeutic approaches to overcome inappropriate leukocyte activation and accumulation seen in ageing and IMIDs. Production of these immunopeptide(s) decreases with age, potentially contributing to inappropriate migration of leukocytes. Crucially we can rescue this defect by administering a synthetic version of the peptide. However, these synthetic compounds are quickly removed from the circulation, making them an unsuitable as drugs. Therefore, we urgently need to formulate a drug delivery system to improve stability, minimising dosing regime and maximise therapeutic effects of our novel immunopeptides.
This project has two major aims:
1. To design and formulate novel drug delivery systems encapsulating immunopeptides and evaluate their stability, pharmacokinetics, and pharmacodynamics.
2. To test the therapeutic efficacy of the encapsulated immunopeptides in models of antigenic response and acute inflammation in healthy young and aged subjects.
WP1: Building on preliminary data, we will initially assess the size, stability, and release rate of the pilot liposome-immunopeptide using a combination of dynamic light scattering, electron microscopy, western blot, and mass spectrometry analysis. Subsequently we will investigate how altering the lipid composition (e.g., by addition of cholesterol or changing surface properties) of the liposomes impacts these parameters. As lipid scavengers, monocytes may inadvertently phagocytose liposome-encapsulated drugs blocking their therapeutic effects. Using immunoassays and fluorescence microscopy, we will assess the possible phagocytosis of candidate liposome-immunopeptides by human monocytes in vitro. Finally, we will conduct biodistribution, pharmacokinetic and pharmacodynamic studies on labelled peptide nanoformulations administered by various parenteral routes. Data generated will be analysed using common modelling software (e.g., Winonlin). WP2: The next step in the translational pipeline is evaluating the therapeutic efficacy of the compounds on leukocyte trafficking. To achieve this, we will use a combination of in vitro studies using human leukocytes and preclinical murine models of leukocyte trafficking in health, with age and following acute inflammation.
The migration capacity of leukocyte subpopulations and their response to the encapsulated-immunopeptides will be assessed using our well-established in vitro real-time imaging assays. Here we will take advantage of our access to the Birmingham 1000 Elders Cohort to recruit healthy individuals over the age of 65 to assess the effect of age on these responses. Simultaneously, we will investigate the effects of the liposome-immunopeptides on leukocyte trafficking through
(i) lymphoid tissues in response to antigenic stimulation and
(ii) into peripheral tissues in response to acute inflammation (zymosan-induced peritonitis).
Our data indicates that the immunopeptides regulate migration into peripheral tissues, but do not appear to affect migration into lymph node. We will formerly test this by using e.g., mBSA or OVA model, thus providing crucial understanding of the involvement, if any, of these immunopeptides in antigen-driven responses. We will also investigate whether the liposome-immunopeptides can reverse the age-associated defects in leukocyte trafficking and tissue repair. Ultimately, we will generate a new suite of nanoencaspulated immunopeptides for therapeutic use.
For further information on the MIBTP2020 scheme and to apply please visit the following sites - https://warwick.ac.uk/mibtp/ and https://www.birmingham.ac.uk/research/activity/mibtp/index.aspx.
For further project information please contact Dr Helen McGettrick - [Email Address Removed] Funded studentships available to home and international students subject to BBSRC and University of Birmingham eligibility being met.