Tolerance to WIN55,212-2 is delayed in desensitization-resistant S426A/S430A mice

Abstract

Tolerance to cannabinoid agonists can develop through desensitization of the cannabinoid receptor 1 (CB 1 ) following prolonged administration. Desensitization results from phosphorylation of CB 1 by a G protein-coupled receptor kinase (GRK), and subsequent association of the receptor with arrestin. Mice expressing a mutant form of CB 1 , in which the serine residues at two putative phosphorylation sites necessary for desensitization have been replaced by non-phosphorylatable alanines (S426A/S430A), display reduced tolerance to Δ 9 -tetrahydroeannabinol (Δ 9 -THC). Tolerance to the antinociceptive effects of WIN55,212-2 was delayed in S426A/S430A mutants using the tail-flick and formalin tests. However, tolerance to the antinociceptive effects of once daily CP55,940 injections was not significantly delayed in S426A/S430A mutant mice using either of these tests. Interestingly, the dose response curve shifts for the hypothermic and antinociceptive effects of CP55,940 that were induced by chronic treatment with this agonist in wild-type mice were blocked in S426A/S430A mutant mice. Assessment of mechanical allodynia in mice exhibiting chronic cisplatin-evoked neuropathic pain found that tolerance to the anti-allodynic effects WIN55,212-2 but not CP55,940 was delayed in S426A/S430A mice compared to wild-type littermates. Despite these deficits in tolerance, S426A/S430A mutant mice eventually developed tolerance to both WIN55,212-2 and CP55,940 for all pain assays that were examined, suggesting that other mechanisms likely contribute to tolerance for these cannabinoid agonists. These findings suggest that GRK-and (βarrestin2-mediated desensitization of CB 1 may strongly contribute to the rate of tolerance to the antinociceptive effects of WIN55,212-2, and raises the possibility of agonist-specific mechanisms of cannabinoid tolerance.

Protein Interactors and Trafficking Pathways That Regulate the Cannabinoid Type 1 Receptor (CB1R)

“…However, WT and GASP1 knockout mice both developed tolerance to WIN55,21202-mediated hypothermia, potentially due to differences in overlapping expression of CB1R and GASP1 in different brain regions driving diverse mechanisms of tolerance (Martini et al, 2010). However, one limitation of this study when extrapolating the results habitual cannabis users is the use of WIN55,212-2 rather than 9 -THC since desensitization, internalization, recycling, and tolerance are highly agonistspecific (Hsieh et al, 1999;Wu et al, 2008;Martini et al, 2007;Morgan et al, 2014;Nealon et al, 2019). Indeed, a recent study reported that 9 -THC-but not WIN55,212-2mediated tolerance is dependent on c-Jun N-terminal Kinase (JNK) signaling (Henderson-Redmond et al, 2020).…”

“…CB1R desensitization involves GPCR kinase 2/3 (GRK2/3)-mediated phosphorylation of two serine residues (S426 and S430), which recruit β-arrestin 1/2 and prevent G protein coupling (Jin et al, 1999;Kouznetsova et al, 2002;Daigle et al, 2008a;Morgan et al, 2014). Similar to deletion of β-arrestin 2, S426A/S430A knock in mice display reduced tolerance to cannabinoid-mediated pain for some agonists, but not others (Morgan et al, 2014;Nealon et al, 2019).…”

Cannabis use, abuse, and withdrawal: Cannabinergic mechanisms, clinical, and preclinical findings

“…Like many other GPCRs, the CB receptors can also activate signaling through the beta-arrestin protein (Breivogel et al, 2013;Priestley et al, 2017;Tonini et al, 2006). This signaling pathway has been implicated in control of cell surface receptor turnover via mechanisms involving CB1 phosphorylation by a G proteincoupled receptor kinase (GRK) (Jin et al, 1999;Morgan et al, 2014;Nealon et al, 2019;Nguyen et al, 2012). Through these signaling pathways CB receptors can influence a variety of cellular processes, including neurophysiology, membrane protein trafficking and gene expression (Sim-Selley, 2003).…”

The cannabinoid agonist CB-13 produces peripherally mediated analgesia in mice but elicits tolerance and signs of CNS activity with repeated dosing

“…It is unclear how CNS penetrance of CB-13 would lead to anti-allodynic tolerance, as the anti-allodynia caused by CB-13 was shown to be peripheral CB 1 -mediated acutely. One interpretation may be that functional CB 1 desensitization in the central tissues renders peripheral CB 1 activation to become no longer effective as witnessed with other centrally penetrant cannabinoid agonists [18,19,40,50,54,71] and upregulation of 2arachidonoylglycerol via monoacylglycerol lipase inhibition [14,39,65]. Further work is needed to better understand the mechanisms underlying anti-allodynic tolerance following repeated activation of CB 1 receptors.…”