Abstract
G-protein coupled receptor-55 (GPR55), an endocannabinoid receptor, is a novel anti-diabetic target. This study aimed to assess the metabolic functionality of GPR55 ligands using CRISPR/Cas9 gene editing to determine their regulatory role in beta cell function and incretin-secreting enteroendocrine cells. A clonal Gpr55 knockout beta cell line was generated by CRISPR/Cas9 gene editing to investigate insulin secretion and Gpr55 signalling. Acute effects of GPR55 agonists were investigated in high fat fed (HFD) diabetic HsdOla:TO (Swiss TO) mice. Atypical and endogenous endocannabinoid ligands (10-7-10-4M) stimulated insulin secretion (p < 0.05-0.001) in rodent (BRIN-BD11) and human (1.1B4) beta cells, with 2-2.7-fold (p < 0.001) increase demonstrated in BRIN-BD11 cells (10-4M). The insulinotropic effect of Abn-CBD (42 %), AM251 (30 %) and PEA (53 %) were impaired (p < 0.05) in Gpr55 knockout BRIN-BD11 cells, with the secretory effect of O-1602 completely abolished (p < 0.001). Gpr55 ablation abolished the release of intracellular Ca2+ upon treatment with O-1602, Abn-CBD and PEA. Upregulation of insulin mRNA by Abn-CBD and AM251 (1.7-3-fold; p < 0.01) was greatly diminished (p < 0.001) in Gpr55 null cells. Orally administered Abn-CBD and AM251 (0.1 μmol/kgBW) improved GIP (p < 0.05-p < 0.01), GLP-1 (p < 0.05-p < 0.001), glucose tolerance (p < 0.001) and circulating insulin (p < 0.05-p < 0.001) in HFD diabetic mice. Abn-CBD in combination therapy with DPP-IV inhibitor (Sitagliptin) resulted in greater improvement in glucose tolerance (p < 0.05) and insulin release (p < 0.05). Antagonism of Gpr55 in-vivo attenuated the glucoregulatory effects of Abn-CBD (p < 0.05). Conclusively, GPR55 agonists enhance insulin, GIP and GLP-1 release, thereby promoting GPR55 agonist monotherapy and combinational therapy as a novel approach for the treatment of type-2-diabetes.
Original language | English |
---|---|
Article number | 170251 |
Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | Peptides |
Volume | 125 |
Early online date | 7 Jan 2020 |
DOIs | |
Publication status | Published (in print/issue) - 31 Mar 2020 |
Keywords
- Cannabinoid
- CRISPR/Cas9
- GIP
- GLP-1
- GPR55
- Insulin
Fingerprint
Dive into the research topics of 'CRISPR/Cas9 gene editing demonstrates metabolic importance of GPR55 in the modulation of GIP release and pancreatic beta cell function'. Together they form a unique fingerprint.Profiles
-
Aine McKillop
- School of Biomedical Sciences - Associate Dean (Academic Quality and Student Experience)
- Faculty Of Life & Health Sciences - Full Professor
Person: Academic