Characterizing novel protease activated receptor 2 compounds for potential use in examining depression-like behavior

Student thesis: Master's Thesis


Aims: Globally, depression is considered to be one of the leading causes of disability. Recently, it has been proposed that neuroinflammation is a key process underlying the pathology of depression, especially given the well-established increase in pro-inflammatory cytokines observed in depressed patients. Particularly, the G-protein coupled receptor (GPCR) protease activated receptor 2 (PAR2) has received interest towards its link with depression, as this has shown to play a pro-inflammatory role in disorders of the central nervous system (CNS). However, previously it has remained a challenge to examine PAR2 involvement in depression-like behavior due to the limited agonists and antagonists available. To address this issue, we aimed to investigate the selectivity of the proposed PAR2 small molecule agonist AC264613, which induces depression-like behavior in mice, by testing and comparing this to another GPCR, Mas-related G-protein coupled receptor C11 (MrgprC11), which has been proposed to underlie certain off-target effects of PAR2 activators. In addition, we also planned to characterize the selectivity of the recently developed PAR2 negative allosteric modulator (NAM) AZ8838.;Methods: The selectivity of SLIGRL-NH2 and AC264613 was examined by transfecting tsA201 cells with either PAR2-YFP or MrgprC11-YFP, which were then exposed to the proposed activators and imaged using the epifluorescence microscope. Receptor internalization ratios were performed on individual cells and all statistical analysis was carried out using one-way analysis of variance (ANOVA) followed by a Tukey post-hoc test where appropriate, with P ≤ 0.05 representing a statistical significance.;Results: SLIGRL-NH2 induced receptor internalization for both PAR2-YFP and MrgprC11-YFP. Similarly, AC264613 induced PAR2 internalization but was without effect on the MrgprC11-YFP receptor. Due to COVID-19, characterization of AZ8838 was not undertaken.;Conclusions: In this study, we report successful receptor expression of PAR2-YFP and MrgprC11-YFP in tsA201 cells. Consistent with previous studies, we show that SLIGRL-NH2 is non-specific for PAR2 whereas we confirmed that AC264613 is PAR2 selective. Thus, we conclude that the depression-like behavior, observed following AC264613 administration are mediated via PAR2 mediated signalling. Keywords: Depression, neuroinflammation, PAR2, MrgprC11, AC264613, SLIGRL-NH2, receptor internalization
Date of Award11 Nov 2020
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsEPSRC (Engineering and Physical Sciences Research Council)

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