Aims: Proteinase-activated receptor 2 (PAR2), a GPCR subtype with a novel activation mechanism, has recently received increasing interest due to its potential neuroprotective role in CNS diseases. Investigating the role and properties of PAR2 in CNS was previously made difficult by the limited selectivity and potency of available activators. Recently however, novel PAR2 activators have been developed allowing further characterisation and investigation. Methods: Ca2+ imaging was performed on rat primary hippocampal cultures used at 10-14 DIV. Internalisation studies were performed using PAR2 transfected tsA-201 cells. Mice pup organotypic hippocampal slices were prepared with protection against kainite (KA)-induced neurotoxicity investigated from 15 DIV. Finally, effects of PAR2 activation were assessed in vivo on cardiac function, on behaviour such as locomotion and anxiety and in the EAE mouse model of MS. Statistical analysis were performed using one or two-way ANOVA and Dunnett’s or Bonferroni post hoc tests for multiple comparisons, with p <0.05 considered as significant. Results: In this report we have been able to study the effects of PAR2 activation in CNS preparations where we monitored comparable increases in Ca2+ concentration to those seen in previous studies following application of peptide-based activators. Furthermore, the proposed PAR2 antagonist GB88, while not inducing changes in Ca2+ concentrations, led to PAR2 internalisation, therefore suggesting it is a biased agonist.Additionally, we have shown in an ex vivo model of excito-toxicity, consistent and long lasting beneficial effects of PAR2 activation. Finally, in the EAE model of CNS inflammation, we have detected beneficial effects induced by PAR2 activation including decreases clinical signs intensity as well as in the relapses occurrence and intensity furthermore, looking at the cytokine profiles, we were able to identify correlations between PAR2 activation and IL-6 production. Conclusions: The results presented in this thesis establish PAR2 activation as neuroprotective in vitro and in vivo in the context of neurodegeneration, thus constituting a solid foundation to establish PAR2 as an intriguing potential target for CNS drug discovery and suggest that modulation of its expression or function may be a viable strategy in the treatment of a large range of CNS diseases.
|Date of Award||17 Mar 2017|
- University Of Strathclyde
|Sponsors||Eli Lilly and Co Limited & University of Strathclyde|
|Supervisor||Trevor Bushell (Supervisor) & Robin Plevin (Supervisor)|